Digestive Diseases and Sciences, Vol. 32, No. 8 (August 1987), pp. 900-932

Abstracts of the Eleventh International Symposium on Gastrointestinal Motility September 7-11, 1987

Oxford, England

The following are abstracts of the oral and poster presentations selected for the Symposium program by the International Steering Committee (Chairman: Dr. D.L. Wingate). CNOLINERGIC REFLEX ACTIVATION OF CANINE PYLORIC MOTOR ACTIVITY FROM THE PROXIMAL DUODENUM IN YIVO. H.D. Allescher, E.E. Daniel, J. Dent, F. Kostolanska J.E.T. Fox. Dept. of Neuroscience, MeMaster University, Hamilton, Canada LSN 3Z5. In 16 choralose-urethane anesthetized dogs a manometric assembly was inserted via a gastrostomy, to monitor pyloric pressure with a sleeve sensor. Antral and duodenal contractions were monitored with both manometric side holes and serosal strain gauges. An additional tube channel allowed intraduodenal infusions 1-2 cm aborad from the pylorus. Intrinsic nerves could be stimulated with subserosally implanted silver electrodes 3-4 cm aborad from the pylorus. Field stimulation of the duodenum with 0.5 pps, 0.5 ms, 40 V elicited strong, pyloric contractions not related to antral or duodenal contractions, which could be blocked.by atropine (30 ~g/kg i.v.) or hexamethonium (i0 mg/kg i.v.) and duodenal transection, but were unaffected by naloxone (200 ~g/kg i.v.). Intraluminal infused hydrochloric acid (0.i N, 0.92 ml/min, 2 min) reproducihly caused activation of pyloric motor activity and peristaltic duodenal activity. An excitatory responses could also be elicited by infusion of phenylbiguanide (stimulant of sensory nerve endings) or capsaicin (I0 -s M, 0.92 ml/min), but not by control infusions with diluent (Krebs buffer). The activation of pyloric moforaetivity induced by intraduodenal acid was blocked by intraduodenal infusion of 2% xylocaine (i0 ml) and markedly reduced by atropine and hexamenthonium, hut unaffected by naloxone. This results demonstrate that duodenal nerve stimulation and intralnminal stimuli cause excitation of pyloric motor activity by a pathway involving cholinergic neurotransmission. This suggests the existence of an cholinergic intramural nerve mediated reflex going from the duodenum to the pylorus in response to intraluminal stimuli. Afferent sensory neurons sensitive to capciasin could mediate the response from the mucosa to the myenteric plexus. In the dog endogenous opioid peptides do not contribute in the excitatory reflexe pathway utilized by intraluminal stimuli like intraduodenal acid. Supp.by MRC of Can.and DFG A1 245.

PROPULSIVE

OF

THE

SYNAPTIC INPUT TO NEURONS M E S E N T E R I C GANGLIOm. T.L.

CONTRACTIONS

IN

COLON THE

INHIBIT

GUINEA

EXCITATORy

PIG

INFERIOR

A n t h o n y and D.L. Kreulen. University of Arizona, Tucson~

Department of Pharmacology, AZ 85724 U.S.A. D i s t e n s i o n of the distal colon of guinea pig evokes excitatory cholinergic and n o n c h o l i n e r g i c synaptic potentials in neurons of the inferior mesenteric ganglion. The frequency and amplitude of fast cholinergic e.p.s.p.s and the amplitude of noncholinergic slow e.p.s.p.s are proportional to the colonic intraluminal pressure up to 25 cm H20. In these experiments the colon was attached to a manometer system which permitted propulsive contractions of the colon to propel fluid from the colonic lumen to the manometer. Colonic segments were distended to 20 cm H20 for 2 min during simultaneous recording of intracellular potentials in ganglionic neurons. In all preparations, distension induced vigorous segmenting activity which was interrupted 2-5 times per minute by sustained contractions of the entire colonic segment. In 87% of distensions (34 cells, 21 preparations) the sustained contractions were associated with a cessation of fast cholinergic e.p.s.p.s and partial repolarization of the distension-induced slow e.p.s.p. When the colon relaxed, fluid reentered from the manometer and redistended the colon. The redistension was associated with a rapid increase in fast and s l o w e.p.s.p.s. If the manometer was closed so that the colon contracted isbvolumetrically, the periodic contractions elevated intraluminal pressure to >35 cm H20 but excitatory input to the ganglionic neurons was not i n h i b i t e d . Application of norepinephrine (10-5M) resulted in complete inhibition of sustained propulsive contractions and a reduction of excitatory cholinergic and noncholinergic synaptic input to g a n g l i o n i c neurons. Thus, mechanorecep~ors in distal colon of guinea pig colon behave like length receptors and their activity is diminished by sustained p r o p u l s i v e contractions of the colon. This suggests that during propulsive contractions (mass movements) but not during segmenting contractions the sympathetic out flow to the colon would be inhibited. Support HL27781, DK36289.

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Digestive D&eases and Sconces, Vol. 32, No. 8 (August 1987) 0163-2116/87/080(M1900505.00/0 9 1987 Plenum Publishing Corporation

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY ELECTROMYOGRAPHY OF J-SHAPED ILEAL RESERVOIRS. D.N. Armstrong, L. Sillin, A. Bortoff, K. Snyder. Debts. of Surgery and Physiology, SUNY Health Science Center and VAMC, Syracuse, NY 13210 USA. Ileoanal anastomosis was performed in 6 dogs after total colectomy, rectal mucosectomy and construction of I0 em J-shaped ileal reservoirs. Five bipolar electrode/ strain gage combinations (ESGs #1-5) were sutured to the serosal surface of the ileum starting proximal to the entrance to the reservoir and at 4 sites around the component limbs. After an 18 hour fast, recordings were made for an average of 6 hours/dog at 2 week intervals. Recordings were analysed visually in i0 minute blocks. Animals have been recorded up to i0 weeks postoperatively and a total of 136 hours of records obtained. The classic MMC seen in normal ileum was replaced with characteristic patterns of activity which were consistent between dogs. In the first 2 weeks postoperatively (Wks 1/2) overall myo_ electrical spike burst activity was low and clustered spike bursts (SBs) were seen in all ESGs lasting 1-5 mins and recurring at 15-20 min intervals. These clustered SBS became more frequent with time and by Wks 5/6 recurred at 2-4 min intervals. This frequency remained similar up to Wks 9/10. The SBs became migratory at an early stage, up to 45% passing in an orad direction in Wks 1/2, although by Wks 3/4, over 90% migrated in an aborad direction, each accompanied by recorded contractile activity. The mean migratory velocity of the clustered SBs was 1.38 i 0.39 mmsec and remained unchanged up to Wks 9/10. After Wks 3/4 the regular, clustered nature of the spike activity in the proximal ESGs was replaced by intermittent individual spiking which was not accompanied by recorded contractile activity. However, the aborally migrating SBS in ESGs 4 and 5, located in the limb distal to the ileoanal anastomosis, persisted throughout this time. Thus, the electromyographic activity of J-shaped ileal reservoirs is different from normal ileum. The coordinated, aborally migrating SBs seen in the distal electrodes may have a functional antidiarrhoeal action.

VESICO-RECTOANAL INTERRELATION IN NORMAL AND PARAPLEGIC SUBJECTS D Badiali, G Bausano, E Corazziari, P Magrini, M De Vecchis *, L Cuneo*, A Rizzotto**, G Ronzoni*. Cattedra di Gastroenterologia l,Universita' "La Sapienza" ,*Servizio di Urologia, Casadi Cura Villa Mafalda, **Ospedale Militare Principale Cello, Roma, Italy Recto-anal and vesico-urethral tracts share a commoninnervation which enables concomitant continency in resting conditions and asynchronism of function during micturition and defecation.ln the attempt to evaluate whether the higher nervous centres have a role in the control of the rectoanal-vesicourethral interrelationship, rectoanal motility in basal conditions and during micturition was investigated in 6 male controls (mean age: 20 yrs,range 19-22) and 20 patients ( M 19 ,F 1 ;mean age 38.5 yrs,range 29-56 )with complete spinal cord lesion above the lumbo-sacral parasympathetic outflow.Proximal and distal anal pressures were recorded by means of perfused side-hole catheter; a latex balloon attached to the tip of the manometric catheter was intermittently distended (10,20,40,80,120 ml of air) to evaluate AV/6P in the rectal ampulla; electromyographyof the external anal sphincter (EAS) was recorded in a bipolar manner with steel needle electrodes implanted in the anal margin;cystomanometrywas performed by introducing carbon dioxide into the bladder through a transurethral catheter at a rate of 60 ml/min while recording intravesical pressure. All signals from the anorecta] area and the bladder were simultaneously recorded. Results. Rectal compliance was greater in paraplegics than in controls at rectal distension with 80 and 120 ml (p
DECREASED POTASSIUM CONDUCTANCE AS A POSSIBLE MECHANISM FOR THE ACTION OF CARBACHOL ON COLONIC SMOOTH MUSCLE. C. Bara]as-L6pez and J.D. Huizinga~ I.D.R.U. McMaster University, Hamilton, Ontario, Canada. The musearinic agonist carbachol changes myogenic electrical and contractile activity in dog colon circular muscle (J. Pharmacol. Exp. Ther. 1984; 231:692). We investigated its action on intraeellular electrical activity (in an Abe-Tomita type chamber), from both the submucosal (S) and myenteric plexus (M) surface of the circular layer. A possible mechanism of action was investigated by comparing carbaehol effects (IO-7M) with those of the potassium conductance blockers 9-aminoacridine (9-AA, l-2x10-4M) and tetraethylammoni~un (TEA, 30 mM), A heterogeneity in electrical activities was observed: the resting potential was -71.4 mV (S), -62.9 mV (M); the upstroke amplitude was 40.3 mY (S), 15.7 mY (M); the slow wave plateau amplitude 37.3 mV (S), 8.9 mV (M) and its frequency 4,9 cpm (S), 4.8 cpm (M), Carbaehol, 9-AA and TEA produced a depolarization of 3-12 mV associated with a decrease in membrane conductance, at both surfaces. Carbachol and 9-AA invariably caused an increase in slow wave duration and a decrease in frequency. TEA induced a similar effect in half of the preparations studied. All drugs c a u s e d oscillatory activity (20 to 28 cpm; <2 s duration) which occurred on the plateau phase, The oscillations reached an amplitude of i0 to 25 mV in myenteric plexus surface cells in 8 out of 14 strips and in submucosal surface cells in 4 out of 25 strips. Increase in plateau duration and occurrence of superimposed oscillatory activity was associated with eontractile activity, Conclusions: Electrical activity at both surfaces of the circular muscle layer is heterogeneous suggesting origin of slow wave activity at the submucosal side. Occurrence of up to 44 mV upstroke potentials at the myenterie plexus side (similar to submueosal surface cells) suggests that at least part of the activity is actively propagated, Changes induced by earbachol are likely mediated by a decrease in membrane potassium conductance. Supported by MRC Canada and the CFIC.

ELECTROPHYSIOLOGICAL LOCALIZATION OF DORSAL GASTRIC VAGAL PROJECTIONS TO THE BRAINSTEM OF THE CAT. W.D. Barber, C.S. Yuan and T.F. Burks. Departments of Anatomy and Pharmacology, College o f Medicine, U n i v e r s i t y of Arizona, Tucson, AZ 85724. Dorsal g a s t r i c vagal p r o j e c t i o n s t o the dorsomedial region o f the caudal brainstem were examined e l e c t r o p h y s i o l o g i c a l l y in cats a n e s t h e t i z e d w i t h halothane and n i t r o u s oxide supplemented with oxygen. Single shock s t i m u l a t i o n (0.3 msec, 500 uA, 0.5 Hz) was applied t o t h e dorsal g a s t r i c branch o f the vagus t o a c t i v a t e C f i b e r s which serve the dorsal proximal stomach. Sing]e u n i t a c t i v i t y was recorded e x t r a c e l l u l a r l y from 108 neurons in both sides o f the caudal brainstem during dorsal g a s t r i c nerve s t i m u l a t i o n . Based upon s t e r e o t a x i c coordinates and e l e c t r o p h y s i o l o g i c a l c o r r e l a t e s , the r e s u l t s showed t h a t the u n i t s responding t o dorsal g a s t r i c vagal s t i m u l a t i o n were l o c a t e d in the region of nucleus s o l i t a r i u s , s i m i l a r t o the l o c a t i o n of the responses to g a s t r i c d i s t e n t i o n reported p r e v i o u s l y in our l a b o r a t o r y (W.D. Barber and T.F. Burks, 1983). The l a t e n c i e s o f the u n i t a r y discharges ranged from 189 t o 415 msec w i t h a mean o f 295 • 49.1 msec, suggesting t h a t the dorsal g a s t r i c branch o f t h e vagus is composed o f a large number o f unmyelinated f i b e r s . The conduction v e l o c i t i e s were less than i m/sec based upon the l a t e n c i e s of the brainstem responses. The m a j o r i t y o f the u n i t a r y responses contained m u l t i p l e spikes. Decreasing the stimulus s t r e n g t h reduced the number of u n i t a r y discharges, w i t h the f i r s t spike showing j i t t e r , suggesting an orthodromic response. E l e c t r o p h y s i o l o g i c a l l y , the brainstem p r o j e c t i o n s of the dorsal g a s t r i c nerve were s i m i l a r g e o g r a p h i c a l l y t o those of the v e n t r a l g a s t r i c nerve. These r e s u l t s e l e c t r o p h y s i o l o g i c a l l y c h a r a c t e r i z e g a s t r i c vagal-brainstem neuronal i n t e r a c t i o n s and l o c a l i z e s i t e s o f 2nd or higher order neurons. These data add important i n f o r m a t i o n and extend our understanding of the r o l e of g a s t r i c vagal i n p u t in molding and shaping brainstem a c t i v i t y which regulates the stomach, (Supported by USPHS Grants AM31804, DK36289 and DK35434).

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY MAPPED CLOCK OSCILLATORS: THEIR USE TO MODEL GASTRIC ECA. B.L. Bardak~ian and S.D. Bot. Institute of B i o m e d i c a l E n g i n e e r i n g , University of Toronto, Toronto, O n t a r i o , C a n a d a M 5 S IA4. A m a p p e d c l o c k o s c i l l a t o r (MCO) consists of two i n t e r c o n n e c t e d units: a clock, and a m a p p i n g unit to t r a n s f o r m the c l o c k v a r i a b l e s onto an observable output oscillation. If the mapping unit is a s s u m e d to r e s i d e in t h e cell membrane t h e n t h e c l o c k m a y r e s i d e t h e r e or e l s e w h e r e . The intrinsic parameters of a M C O c a n be estimated directly from intracellular electrical recordings of i n t r i n s i c E C A (or s l o w waves). The frequency and p h a s e lag c h a r a c t e r i s t i c s of g a s t r i c E C A h a s been m o d e l l e d u s i n g an a r r a y of 13 bidireetionally coupled relaxation oscillators (Am.J. Digest. Dis. 1972, 17:299). The model incorporated an i n t r i n s i c f r e q u e n c y g r a d i e n t b u t not the intrinsic a m p l i t u d e and resting potential gradients that w e r e r e p o r t e d in c a n i n e stomach (J. Physiol. 1978, 279:291). T h i s s t u d y a i m s at i n v e s t i g a t i n g M C O s and t h e i r use in a g a s t r i c E C A model that incorperates intrinsic frequency, amplitude and resting potential gradients. Methods: Intrinsic p a r a m e t e r s f o r 13 M C O s were estimated using reported biological data about the i n t r i n s i c g a s t r i c ECA. Two s y m m e t r i c arrays of 13 s u c h M C O s w e r e i m p l e m e n t e d on a c o m p u t e r to form a t u b u l a r s t r u c t u r e of 26 bidireetionally coupled MCOs. The coupling was adjusted to produce the reported frequency and phase lag characteristics of c a n i n e g a s t r i c ECA. R~sultN: I) The i n t r i n s i c o u t p u t of a M C O is quantitat i v e l y s i m i l a r to an i n t r a c e l l u l a r l y r e c o r d e d intrinsic ECA. 2) T h e c o u p l e d M C O s s y n c h r o n i z e d at a f r e q u e n c y of 4.4 c / m i n w i t h a d i s t a l decrease in t h e i r p h a s e lags. 3) A p p l i c a t i o n of DC s t i m u l i to t h e p r o x i m a l ring, to s i m u l a t e the e f f e c t of the fundus, influences the whole population. C o n c l u s i o n : M C O s c a n b e u s e d to m o d e l the d y n a m i c b e h a v i o r of g a s t r i c E C A in a q u a n t i t a t i v e m a n n e r .

CHOLECYSTOKININ (CCK) MODULATESSYNAPTIC TRANSMISSION IN INTRAMURAL GANGLIA OF OPOSSUMGALLBLADDER. A.J. Bauer, T.C. Muir. M, Hanani and J.H. Szurszewski. MayoMedical School, Rochester, MN 55905, USA, Postprandial neural a c t i v i t y is important in regulating contractile a c t i v i t y of the gallbladder (GB), but intramural GB ganglia and their modulation have not been investigated. The purposes of this study were f i r s t to characterize the morphology, electrical properties and synaptic inputs of intramural GB neurons and second to determine the effect of CCK on these neurons. ACHesterase staining showed that the GB contained 17 ganglia/cm 2 with an average of 10 cells/ganglia. Ganglia were clustered along nerve fibers or at the junction of fibers. Intracellular recordings from 76 cells demonstrated intramural neurons had a mean RMP of -54 f 0.8 mV (SEM). The action potential (AP) averaged 64 • 1.8 mV (SEM) in amplitude and had a mean after-hyperpolarization of 12 • 0.6 mV (SEM) with a mean duration to 90% repolarization of 29 • 4.5 msec (SEM). Threshold depolarization using intracellular current (0.52 hA) averaged 16 • 0.6 mV (SEM). During suprathreshold intracellular current injection of several seconds duration, 63% of cells responded with a tonic f i r i n g pattern and 33% with a phasic f i r i n g pattern. Membranetime constant averaged 5.5 ~ 0.5 msec (SEM) and input resistance averaged 36 • 4.0 Mohm (SEM). Stimulation of central efferent or peripheral postganglionic nerve fibers elicited multiple nicotinic fast EPSPs which summated to produce APs. Slow EPSPs were observed in 21% of cells following high frequency (20 Hz) intergangljRnic nerve stimulation. Superfusion of CCK as low as 10-zu M increased the amplitude of fast EPSPs evoked by interganglionic nerve stimulation in 50% of cells tested (N=14). Frequently, CCK converted subthreshold fast EPSPs to APs. This action appeared to be presynaptic because CCK had no effect on membrane potential, input r~sistance or local application of acetylcholine (i0 -~ M). Since CCK is known to f a c i l i t a t e GB emptying, these data provide direct evidence for a neural mechanism of action for CCK in addition to its myogenic action. (Supported by DK 17632 and DK 07198.)

CHARACTERIZATION OF SEROTONIN (5-HT) CONTRACTILE RECEPTORS ON LOWER ESOPHAGEAL SPHINCTER (LES) MUSCLE: IDENTIFICATION OF A NOVEL SEROTONERGIC AGONIST, SK&F 103829. M.S. Barnette, H.S. Ormsbee IIl, F.C. Barone, M. Grous, C.D. Mannin$, and W.E. Bondinell. Smith Kline & French Laboratories, Philadelphia, PA 19101. In anesthetized dogs, SK&F 103829 (2,3,4,5-tetrahydro8-methylsulfonyl-iH-3-benzazepin-7-ol, hydrobromide) produces a significant elevation in LES pressure that is blocked by ketanserin but not by atropine. To further characterize this response, we examined the ability of both 5-HT and SK&F 103829 to contract isolated canine LES circular smooth muscle. LES muscle strips relaxed to electrical field stimulation and demonstrated concentration-related contractions to serial additions of both 5-HT(EC50=0.3 ~M) and SK&F 103829 (EC50=1.6 pM) that were not affected by desmethylimipramine (0.1~M) or fluoxetine (0.1pM). 5-HT and SK&F 103829 were antagonized by methysergide (PKB=8.7 and 9.3), ketanserin (pKB=9.0 and 8.9) and LY 53857 (pKB=7.8 and 7.9)7 suggesting that both compounds contract the canine LES by acting directly at 5-NT 2 receptors. Pretreatment of the muscle strips with phenoxybenzamine (I0 ~M for 30 min) produced a significantly greater inhibition of the maximum contractile responses to SK&F 103829 (81%) than to 5-HT (62%), indicating that SK&F 103829 acts as a partial agonist. Depletion of extracellular Ca 2+ attenuated the contraction elicited by both substances. Pretreatment of the LES smooth muscle with nifedipine (50nM) inhibited both 5-HT(44%)- and SK&F 103829(54%)induced maximum contractions. Results obtained in canine LES were compared with those obtained in isolated rings of the rat aorta, a preparation known to contain 5-HT 2 receptors. Serial additions of 5-HT (EC50=2.1 ~M) and SK&F 103829 (EC50=8.6 ~M) in this preparation produced a concentration-related contraction. Furthermore, these contractions were antagonized in a similar manner by methysergide (pKB=9.4 and 9.9), ketanserin (pKB=9.1 and 9.5), and LY 53857 (pKB=7.96 and 8.7). Therefore, the canine LES contains a 5-HT 2 receptor which is a target for SK&F 103829, a partial 5-HT agonist.

EFFECT OF ELECTRICAL STIMULATION ON GASTRIC EMPTYING. Bader-E. Bellahsene~ Bruce Schirmer~ Otis Updike and Richard McCallum. University of Virginia Medical Center, Charlottesville, VA 22908 USA We used electrical stimulation to facilitate gastric emptying in a volunteering patient with severe gastric stasis who had undergone an antrectomy for diabetic gastroparesis refractory to all medical management. Seven monopolar 28-gauge stainless steel electrodes (A&E Medical Corp., NJ) were implanted at surgery. One pair of electrodes was located in the fundus, one pair in the most distal corpus, one pair in the proximal duodenum and the reference electrode was located in the jejunum. Electrogastrograms were obtained before and after the surgery, and at each stimulation session, the latter studies commencing 1 month postoperative. Gastric emptying was performed scintigraphically using a meal of chicken liver labeled with 99mTc-sulfur colloid and mixed with beefstew. The stimulation was initiated 30 min before eating the meal and was continued for 120 min while gastric emptying was simultaneously assessed by a gamma camera. The stimulating pulse was biphasic and had an amplitude of i0 V. The current delivered was constant and set at 2mA, after detecting the threshold of sensation between 3.5 and 4mA. The frequency of the pulse was set at 3/min and was generated by a World Precision Instrument (WPI) stimulator model A310 isolated by a WPI isolator model A350D for some patients with delayed gastric emptying. The pulse was delivered to the proximal pair of gastric electrodes and electrogastrograms were obtained from the distal pair as well as from the duodenum. No evidence of a gastric dysrhythmia was initially observed. Four gastric emptying tests were performed without stimulation and 6 with the stimulation. 60 min after ingesting the meal 61% of isotope remained in the stomach and 41% after 120 min, compared to 97% and 83% respectively without the stimulation (normal result for this meal p<70% retained in 2 hrs). In conclusion, we successfully stimulated the stomach using an external stimulator and induced an acceleration of gastric emptying. Electrical stimulation may prove to be a promising therapy for some patients with delayed emptying.

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY ENKEPHALIN- BUT NOT MOTILIN-INDUCED GUT STIMULATION IS VIP SENSITIVE. M, Bickel. Hoechst AG, D-6230 Frankfurt FRG Enkephalins stimulate phasic contractions of the gut in r a t s , cats, dogs and humans. Recently i t has been reported that opiate egonists,morphine and enkephalin analogues

i n i t i a t e premature migrating motor complexes (MMC) in the small intestine of the dog, which could be prevented by the opiate antagonist naloxone (IRCS Mad. Sci. ]985, 13:625, Gastroenterology 1984, 86:662). Motilin is longer known to generate MMC's in the canine gut (Digestion 1975, 13:246, Scand. J. Gastroenterol. 1976, Suppl. 39:93). The aim of our study was to compare the characteristics of the enkephalinand motilin-induced events at the small intestine of dogs. Three bipolar platin electrodes were chronically implanted in the duodenum, jejunum and ileum of male Beagle dogs. Only phase I I I electric activity was analysed for amplitude and frequency and duration of spike burst and duration of cycles. In control experiments regular electric migrating complexes (N4C's) were seen at periods of llO + lO min. Motilin (lpg/kg i . v . ) and the synthetic enkephalin analogue HOE 825, H-Tyr-D-Lys (For)-gly-Phe-homocysteine-thiolactone (3pg/kg i . v . ) in all eases induced an immediate premature MMC. The drug induced MMC's migrated aboralIy much faster than the regular activity fronts. Naloxone inhibited the enkephalinbut not the motilin-induced fronts. In contrary atropine abolished completely the motilin effect but only partially the enkephalin action. Vasoactive intestinal polypeptide VIP antagonised the enkephalin action but was without effect on motilin-induced fronts. The data suggest that motilin and enkephalin act by completely different pathways. Whereas motilin seems to stimulate gut contractions directly by a cholinergic pathway, the enkephalin might rather inhibit the inhibitory control of the VIP-ergic system on the gut and thus leading indirectly to a stimulation of gut motility. STIMULATION OF ANTERIOR SACRAL NERVE ROOTS IN MAN: THE PROXIMAL EXTENT AND DIFFERENTIAL EFFECTS ON COLONIC MOTILITY. N R Binnie, P Edmond, G H Creasey, A N Smith. Spinal Injur-ies Unit and Gastrointestinal Unit, Western General Hospital, Edinburgh EH4 2XU, Scotland. Brindley introduced sacral a n t e r i o r root stimulators f o r bladder control in paraplegic subjects. Using his device the d i f f e r e n t i a l e f f e c t s of sacral a n t e r i o r root stimulation on anal sphincter and colorectal m o t i l i t y , was d i r e c t l y studied f o r the f i r s t time in s p i n a l l y injured man by Varma et al (Br J Surg 1986; 73: 478-482). The present study ascertains the nature and proximal extent of the colonic m o t i l i t y response to sacral nerve root stimulation in six male paraplegic subjects. With endoscopic access, pressure recordings were taken from the transverse colon and continued d i s t a l l y using conventional manometric methods. There was a pressure increase in response to $2 and $4 (15 + / - I0 cm of water) but $3 stimulation caused the greatest pressure response (45 + / - 20 cm of water). This response affected a l l of the l e f t colon but in three subjects i t was also r e g i s : t r a b l e IO cm proximal to the splenic flexure, confirmed radiological':y. In the lower l e f t colon these motor responses resembled p e r i s t a l s i s because they were propagated d i s t a l l y between three pressure transducers in series, This study establishes that the extent of colonic motor response to sacral root stimulation may extend proximal to the splenic f l e x u r e and suggests that the $3 root is the dominant spinal nerve root f o r e l i c i t a t i o n of m o t i l i t y responses in the l e f t colon.

THE MOTOR RESPONSE OF' THE SMALL INTESTINE TO MLLK FEEDS IN FRETERM 1NFANI'S. W M hisser, J B Watt, R P A Rivers, P J Mills. St Mary's Hospital Medical School and the Department of" Child Health, Institute of" Child Health, London. Smail intestinal motor activity is e h a r a c t e r • by a cyclical pattern of activity which is disrupted by food and i~ replaced by a continuous patte-n. 7n the preterm infant however both patterns are poorly developed. Using constantly perfueed m u l t i l u m e a jejunal catheters we have studied the effect of enteral feeding on small intestinal motor activity In ]0 preterm infants studied on 23 occasions between 28 and 44 weeks gestation. When given a bolus feed appropriate to t~e infants age, the fasting pattern was not disrupted Oh replaced by a fed pattern in the very preter.m infant (28-30 weeks) but disruption and the appearance of the fed pattern increased with increasing gestational age (r=O.6, p=O.OOP), i n c r e a s i n g fasting motor m a t u r a t i o n (r=0.6, p-0.O05), reduced feed frequency (r=0.66, p = 0 . O O 1 ) , i n c r e a s i n g feed volume (r=0.8~ p
RESPONSES OF VAGAL EFFERENT NEURONES TO INTESTINAL ACIDITY AND OSMOLALITY AS COMPARED TO ANTRAL STIMULI - DIFFERENT

MECHANISMS? L.A. Blackshaw and D. Grundy. Dept. of Physiology, The University, Sheffield SI0 2TN, U.N. The common view of the control of gastric emptying by chemical composition of a meal regards the duodenum as the site Of mucosal receptors responding to osmotic, acidic and other chemical stimuli. E!ectrophysiological evidence shows these receptors travelling in the vagus. However, there is also a similar population of receptors in the antrum, yet their role in reflex control of emptying has received little attention. There is also the possibility that these gut receptors are involved in behavioural effects such as satiety, nausea and vomiting. The a i m o f this study was to compare the effects of acidic and osmotic stimuli in the duodenum and the antrum on vagal efferent discharge and the occurrence of vomiting or its prodromata. Efferent unitary recordings were made from the right cervical vagus of the Urethane anaesthetised ferret, and units with respiratory or cardiovascular rhythms discarded. 77% of units were affected by distension of the stomach showing either excitation or inhibition of discharge, always at short latency with marked changes in firing rate. 72% were affected by distension of the intestine in a similar way. In separate experiments either the antrum or the duodenum were perfused with isotonic saline, which was substituted with either 150 mM HCI or 300-500 mM CaCl. The effects of perfuslons on efferent discharge was compared. HCI in the antrum modulated discharge in 31% of efferent units (excitation or inhibition), and 25% when Perfused in the intestine. Hypertonic saline was more effective in the antrum (33%) than in the intestine (7%). However, both Chemicals often caused vomiting when perfused in the intestine, but never in the antrum. These results indicate that mucosal receptors in the antrum contribute as much as, and in some cases more than those in the intestine to the genesis of vago-vagal reflexes, converging with mechanoeensitive inputs. Intestinal chemoreceptors appear to have an additional role as a peripheral trigger for vomiting.

(A-4) Digestive Diseases and Sciences, Vol. 32, No 8 (August 1987)

903

ABSTRACTS OF THE ELEVENTH INJ'ERNATIONAL SYMPOSIUM ON GASTROINTESTIN~ MOTILITY MOTILIN'S TARGET REGION AND ACTIVE PART IN MAN. v.g0~mans, G.Matthijs, T.L.Peeters, W.Eielanski, G.Vantrappen. Center for G ~ o g i c a l Research~ University of Leuven, B-3000 Leaven, Belgium. Based upon physiological studies we suggested that motilin(MOT) is only involved in the regulation of gastric contractile activity. The small intestine is also responsive to MOT but in man few data are avail@ble c0ncerning this point. We have examined the presence of MOT receptors in different regions of the human small intestine by recording the contractile response to MOT of muscle strips and by measuring binding of iodinated MOT to smooth muscle tissue homogenate. Human duodenal (D), jejunal (J) and ileal (I) tissue was "obtained from the operating theater. In "the duodenum four zones each approximately 3.5cm long were studied: D1 (just distal to the py!orus), D2, D3 and D4 (just proximal to the angle of Tre*tz). In the organ bath the maximum response to MOT was 63• (DI), 44i5 (D2), 37• (D3) 23• (D4), 0 (J/ and 0 (I) % of the maximum response to aeetylcholine and was obtained at 10 M porcine nor-leucine MOT. The pD2 was a~ound 7.80• Almost identical results were obtained using canine MOT. The response could not he blocked by TTX or atropine. Homogenates of smooth muscle tissue were studied in binding experiments with iodinated porcine motilin. The receptor density decreased distally 49 (DI), 50 (D2), 20 (D3~, 14 (DI), 0 (J and I) fmol/mg. The affinity constant was similar in the four duodenal regions: 1.8 nM. Canine MOT labeled in its histidine residue showed a similar affinity. The N-terminal pens did not interfere in binding assays nor did it induce contractions. W e conclude that sensitivity t o MOT decreases ra~idly along the h~man duodenum, and is very weak beyond the angle of Treitz. In view of our previous results motilin's target appears to be limited to antrum and upper duodenum. Considering the simil~r hioactiv~ty of canine and porcine MOT in man, the active part of MOT appears s be C-terminal and not N-terminal.

INTESTINAL TRANSIT IN RATS DURING ACUTE :AND ' : ~ C ~ I C MORPHINE ADMINISTRATION AND MORPHINE W I T ~ D R ~ W K L . N.J. Brown & I.M; Coupar. Department of PhysiologY, ~"heUniversity, Sheffield SlO 2TN and School of Pharutaeo~cpf, Victorian College of Pharmacy, Victoria, Australia; It is widely known that acute ~orphine admimistmation delays intestinal transit time in the rat, but the effects of chronic morphine administration on transit are unknown. This study investigates chronic morphine administration and withdrawal on rat intestinal tTansit. 29 rats (Sheffield strain, 250-300g) e~lipped With duodenal cannulae (l-2cm from the pylorus), following recovery were randomly allocated to 5 groups. Two groups were made morphine-dependent by subcutaneous (s.c.) injection of an emulsion delivering 3OQ mg/kg morphine HCI in 3 doses over 48h, and 2 groups given a control emulsion (no morphine). On the day of the study B ml radiol~lled vitafood (Boots CQ~, Ltd,, 25 ~Ci, 99m Technetium) was infused via the duodenal cannula for 90 min into all rats. After 30 min naloxone (lO mg/kg) or saline was injected s,c. Rats were killed after the 90 min infusion and the intestinal distribution of the radiolabelled meal assessed. Results showed no significant differences in the position of the head of the meal (section io and caectmn), the distribution of the ~eal or the geometric centre (GC, section 7 ) between control and morphine dependent rats, even though a n acute dose of morphine (i0 mg/kg S,c. in the final group of rats) retained significant amounts of m~_rker in the stomach (p
EFFECT OF GASTRIC ALKALIZATION ON THE MIGRATING Me

EFFECTS OF NEUROTENSIN ON MOTOR PATTERNS OF TIIE PROXIMAL SMALL INTESTINE IN CONSCIOUS DOGS. S.Bfihner, H.J.Ehrlein.. Institute of Zoophysiology, University of Hohenheim, F:R.G. In this study we investigated the digestive motor patterns of the duodenum and proximal jejunum by means of closely spaced extraluminal transducers and a computerized analysis of contraction spread. The effects of physiological dosages of neurotensin (NT; 2.5 and 5.0 pmol/kg/ min) on both the duodenum and the adjacent jejunum were studied. The test meal was an acaloric meal of cellulose gum. Gastric emptying was measured radiographlcally. The motor patterns of the duodenum and jejunum differed significantly in respect to the frequency of contractions and the length of contraction spread (Tab.). The higher dosage of NT significantly changed the motor pasterns of both the duodenum and jejunum in comparison to saline control infusion: the length of contraction spread was nearly halved, the number of stationary contractions increased, .and contraction frequency decreased (Tab.). The number of contractions spreading from the duodenum to the jejunum was reduced from 20~ to 101. Both dosages of NT slowed the emptying rate of

TOR COMPLEX (INC) IN P A T I E N T S WITH DUODENAL ULCER._iLl.Bortolotti G.Bersani l~.Narinangeli ,L. Bar ba~os.sa, G.Lab~. Dept.Medicine and Gastroenterology,University of Bologna, Italy. In a series of 10 patients with duodenal ulcer (group DU)showing basal and pentagastrin stimulated increased gastric acid secretion, we recorded the gasiroduodenal motor activity with'a

multichanneI probe Ferfused with a pneumo-hYdraulie low-compIia_n ce pump and Connected to external t r a n s d u c e r s and a polygraph, The Study was c a r r i e d out for a basal period of about 300 rain to record a~ least two consecutive MMC-Activity Fronts (A~). Just after the last AF a gastric infusion of isoosmotic solution o f NaHCO3 (0~5 ml/min) was c a r r i e d out for another period of 180 rain. In 5 of these cases an H antagonist,Ranitidine (R),was administered i . v . a t e dose of 1020 rag,30 rain after the beginning of gastric alkalization(GA). In this manner the group DU was subdivided in two subgroups: one with GA 0niy,and the other With GA plus R. A group of I0 subjects with normal acid secretion was used as a control (Group C). The tim e interval between silbsequent

NMC-AFs (MMC cycle length) and the percent Of time occupied by AFs were calculated from duodenal r e c o r d i n g s . RESULTS. In basal conditions the MMC cycle length (-i+_SD) of 1he group DU (139+ 32 rain) was significantly (p< 0.05) longer than controls(9~+15 rain) whereas the percent duration of AF in group DU (3.0+2 %) was significantly s h o r t e r than that of group C (7.9+3 %). GA atone and, more strikingly, GA+R decreased the bINC cycle length to 82+_25 and 59• min, respectively, and increased the percent duration of A F to 7.2_+3 and i0.9=+~ %, respectively. C O N C L U S I O N S . These

data indicate that: i) gastric hypersect-etion observed in duodenal ulcer may be the cause of longer than normal NNC cycle; 2) in fact, gastric alkalization r e s t o r e s in DU a normal NMC cycle length, !ikely by removir~g the inhibitory effect of the acid hypersecretion; the H2 antagonist Ranitidine shortens the MMC cycle not only by increasing gastric pH but also by another unknown mechanism.

the c e l l u l o s e meal ( S a l i n e i 4 . 8 ml/min, NT 2.5 p~ol: 3.9 ml/min, NT 5.0 pmol: 2.4 ml/min). Results show (1) t h a t even a d j a c e n t i n t e s t i n a l segments can e x h i b i t a d i f f e r e n t $ o t o r p a t t e r n , and 42) t h a t NT reduces the p r o p u l s i v e a c t i v i t y o f the duodenum and t h e jejunum in a s i m i l a r way. Duodenum Saline

r5.8

DGS (om ) T 1.3

0.9 + 0.4

NT 2.5 pmol

fi4.6

+ 1.1

1.1 + 0.4

NTje,iunumS.0 pmol

3.7 + 0.6,

Saline NT 2.5 pmol NT 5.0 pmpl

0.9 + 1.7 u 9.0 $ 2.1.

6.8 + 2.2*

S/P

1.4 +- 0.4*

FC (c/min ) 8.9 + 2.4

8.8 u 2.4 [[[iii!7"9 $ 2.2*

0.4 + 0.2 0.6 • 0.2

+ 1.3 + I.i

1.0 + 0.4*

+ 1.6,

*: p
(A-5)

904

Digestive Diseases and Sciences, Vol. 32, No. 8 (August 1987)

ABSTRACFS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY CORTICOTROPIN RELEASING FACTOR MEDIATES MOTILITY EFFECTS OF STRESS. Thomas F. turks and Cynthia L. Williams. Department of Pharmacology, University of Arizona, Tucson, Arizona 85724, U.S.A. Understanding of the etiology of i n t e s t i n a l m o t i l i t y dysfunction due to stress would Be of value in the design of treatment f o r patients with i r r i t a b l e bowel syndrome (IBS) and other stress-related g a s t r o i n t e s t i n a l disorders~ We have developed a nonulcerogenic model of mild stress in rats that mimics, in many respects, stress effects in IBS patients. The model, p a r t i a l wrapping r e s t r a i n t , resulted in elevated plasma levels of ACTH and ~-endorphin, markers of stress responses. Partial r e s t r a i n t stress also produced i n h i b i t i o n of small i n t e s t i n a l t r a n s i t (SIT), stimulation of large i n t e s t i n a l t r a n s i t (LIT), and increase in fecal excretion. The stress-induced i n h i b i t i o n of SIT was not prevented by hypophysectomy or adrenalectomy. The effects of stress on SIT or LIT were not mimicked by exogenously administered ACTH or B-endQrphin in doses that produced plasma levels similar to those generated by stress. Administration of c o r t i c o t r o p i n releasing factor (CRF) i . c . v , or i . v . in doses of 0.3 - 10 ug in nonstressed rats reproduced the effects of stress on SIT, LIT, and fecal excretion. Doses of CRF of 1-10 og also decreased gastric emptying. Administration i . c . v , or i . v . of 50 ug of a peptide CRF antagonist, m-helical CRF-(9-41) resulted in antagonism of effects of exogenous CRF and blockade of the effects of stress on LIT and f e t a l excretion. I t is u n l i k e l y that hypotbalamic CRF produced changes in small or large i n t e s t i n a l t r a n s i t as a result of stimulation of p i t u i t a r y hormone release because the effects of stress on t r a n s i t were not blocked by hypophysectomy or adrenalectomy, nor were stress effects mimicked by exogenous ACTH or g-endorphin. I t is l i k e l y that stressinduced release of CRF alters i n t e s t i n a l m o t i l i t y and t r a n s i t via actions mediated by the autonomic nervous system. (Supported by USPHS grants DA02163 and DK36289.)

PRE-PYLORI~!MECE~NISMS CONTROLLING GASTRIC MOTILITY IN THE C O N S C I O U S DOGs J.S. B u l l , D. Grundy and T. Scrateherd. Dept. of Ph!rsi-ology, The University, Sheffield, sl0 2TN, England. Gastric emptying is a consequence of movements of the gastric corpus; and pyloric antrum. The generally accepted description of the control of this motility and emptying is of a duodenal brake restraining corpus and antral activity to limit the rate at which chyme leaves the stomach. The present study considers pre-pyloric mechanisms controlling Gastric motility in the conscious

dog. Four dogs had their stomach surgically divided into separate corpus and antral pouches and cannulae positioned in each, continuity of the bowel was established by Gastroenterostomy. Experiments were earrled out on fasted animals as they rested comfortably in slings. Pressure in the two Gastric pouches was recorded manometrically from balloons placed in the pouches. MMC activity was characterized by synchronous activity in the corpus and antrum. Slow tonal changes ifi the corpus preceded antral waves by approximately 10s suGGesting a corporo-antral reflex link. This was confirmed by distending the corpu s balloon (with 200 to 400 ml water at 37eC) during phase I of the MMC which immediately initiated low amplitude phasic activity in the antrum. Distension of the antrum with volumes >15ml inhibited corpus contractile activity whether it occurred spontaneously during the active phase Of the MMC or was evoked by corpus distension during phase I. With 50ml in the antrum, there was a pronounced fall in corpus tone and complete inhibition of phasic activity which returned rapidly on deflation. In contrast, antral volumes
MEMBRANE POTENTIAL GRADIENT IN CANINE COLONIC CIRC~ MUSCLE CORRESPONDS TO GRADIENT IN SODIUM PUMP ELECrROGENIC1TY E. P. Burke, J. B. Reed and 142M. Sanders University of Nevada School of Medicine, Reno~ NV 89557 U.s.A. Membrame potential varies from approximately -80 mV to approximately ~10 mV through the thickness of the circular layer in canine colonic mnsclcs. This study tested the hypothes~s that this large gradient in membrane potcnfi~ may be due to a gradient in electrogenie sodium pumping. The effects of sever',d conditions known to block eleetrogenic sodium pumping were tested on resting membrane potentials (RMPs) of colonic muscles. RMPs were recorded with microdectrodes from cells at several positions through the circular layer. Ce]~ adjacent to the submucosal sur~ce d~po!""'a "arid "a by an average of 38 mV in response to ouabaln (10~- 10"~M). Ouabaha did not significantly affect syncytlal input resistance, suggesting that the depo "larlzation was not due to relative ionic pcrmeabdides. Removal of the external K § also depolarized these cells by a similar magnitude. Readnfission of K + (5.9 m M) produced rapid repolarization and hyperpolarizatinn below the original RMP averaging 13 inV. Readmlsslon of 15 mM K +, canscM cells to hypcrpolarize well beyond the estimated E K. Oeabaln hlocked the repolarization in response tO reintroduction of ex/ernal K +. These results strongly suggest that the effects of lowering exter*~al K + were not primaril f dim to a shift in E K. Lowering the bath temperature . . . . rewarmmg repolarn~d to20 C rapidly depolarized membrane potentml; ceils. Ouabain and potassium-free solution blockcd the repolarlzation response to rewarming. Cells aiso dcpoiarizzd whe. exposed to solutions in which the NaC] was replaced with LiCh These data suggest that a significant portion of RMPs of submucosal cells is due to eleetrogenie ion pumping. The RMPs of cells within the bulk of the circular layer were also recorded. RMP deere~tscd as a function of distance from the submncosal border. The RMPs of cells at the myenterlc border of the circular muscle were not significantly affected by either onabain and K + -free solution, The gradient inmembrane potential through the circular layer was abolished by inh~itors of the sodium pump. These + + results suggest: i) An electrogenie Na / K pump contributes significantly to the resting membrane potential of circular cells at the submacosal border; ii) A gradient in pump electrogenicitY appears to be responsible for the membrane potential gradienr across ~ e circular layer. (Sopport~l by NIII Grant AM38717.) o

.

INTERDIGEST!VE ELECTRICAL ACTIVITY AND TRANSIT IN GER?iFREE RATS. Ph, Caenepee1~ J. Janssens, G. Vantrappe% H. Eyssen~ G, Coremans. Center for G.i. Research, University of Leuven, Belgium. Germfree rats have a slower small bowel transit than conventional rats. We examined the effect of absence of a g.i. bacterial flora on the migrating motor complex in proximal and distal small intestine and its possible effect on propulsion of bowel contents. To measure inherdigestive 50% transih time (transit time of 50% of a given test ~ balance) _in germfree and in conven'tional rats, ] m] of C-PEG test substance was administered intragastricaily to 34 fasting male Fisher rats. 7he rats were killed 0.5, i, 2, 3~ 4~ S, 8 and 12 hours after li~he administration of the test substance and the amount of C - P E G was determined in the various small bowel segments. The ~1C was recorded electromyographicatly by means of chronically implanted bipolar 80 p NiCr wire electrodes. Germfree rats were operated in their isolators under strict sterile conditions and were kept there during recovery and during the entire EMG recording period, in a first group of rats (5 germfree~ 3 conventional) 4 electrodes were implanted in the proximal ]/2 of the sm~ll intestine; in a second group (4 germfree~ 6 conventional) 8 electrodes were sutured on hhe distal ]/4 of 8he small bowel.

'

Results (in minu~hesl mean s SD; ~p < 0.05) small bowel segment germfree 50% transit time proximal 3/4 " 91 + 28 distal 1/4 457 + 106 MI4C period proximal 1/2 20 + 3 distal I/4 83 + 17

conventional 25 + 20 } 144 + 29 ~ 13 + 1 ":~ 42 + 9 ~

Conclusions: i. The absence of a g.i. bacterial flora considerably decreases the Cycling frequency of the ~,IC but does net affect the relative number of phase S that reaches the distal ileum. 2. These changes may account for the slowed interdigestive transit in germfree rats. S. it is speculated that the M~C pemiod in germfree rats represents the basic intrlnsic ~]~IC frequency and that the conventional cyciin~ frequency represenhs a bacterial effect upon this basic cycling.

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905

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY THE EFFECTS OF PELVIC NERVE S T I M U L A T I O N ON THE I N T E R N A L A N A L SPHINCTER IN THE CAT. Anders Carlstedt, Stig Fastb, L e i f Hult@n, Svante Nardgren,

Sigv@rd Akerval/ and .Tom Oresland. Oepartrnent of Surgery II Sehlgrenska sjukhuset, S-ql3 q5 G6taborg. Sweden. The internal anal sphincter in the cat (IAS] is under a tonic e x c i t a t o r y influence via the sympathetic hypogastric nerves [H(3N] and the lumbar colonic nerves [LCN), The role of the parasympathetic pelvic nerves (PN] in the control of anal m o t i l i t y is controversial, The purpose of the present investigation was to study l~he effects of pelvic nerve stimulation on IAS m o t i l i t y . M e t h o d : The investigation was performed in 20 cats under chloralose anaesthesia. Anal pressure was recorded by means of a water filled cylindrical cuff [(2) 6 mm), The pudendal nerves were isolated in the iachio-rectal fossae and divided, The pelvic nerves were isolated and divided, HGN and LCN were isolated anc] divided during the course of the experiment, The periferal ends of the divided nerves were mounted on silver ring electrodes for subsequent electrical e f f e r e n t stimulation. Phentolamine and propranolol were used for alpha-and bets-adrenergic receptor blockade. Nor-adrenaline was infused i n t r a - a r t e r i a l l y in the inferior mesenterie a rte ry, Atropine and hexamsthonium were used as muscarinic and nicotinic receptor blockers respectively. Results: Bilateral division of the PN did net change anal pressure, E [ f e r e n t stimulation of PN [PNS, 5Hz, 0,5-5 ms, 8V) elicited a relaxation in the [AS in experiments with intact sympathetic innervation (high anal tone), whereas PNS after division of the sympathetic nerves [low anal tone) caused an anal contraction, Stimulation of sympathetic nerves and administration of noradrenaline elicited a contraction in the lAB, PNS delivered simultaneously with sympathetic nerve stimulation or noradrenaline caused a reduction of anal pressure. The anal contraction elicited by PNS was abolished by phentolamine and reduced or abolished by atropine. The inhibitory responses seen on PNS were unaffected by propranolol, unaffected or increased by atropine and abolished by hexamethonium. Conclusion: The pelvic nerves convey e x c i t a t o r y and inhibitory neurons to the IAS. The present results are consistent with a oholinergic modulation of noradrenaline release from sympathetic nerve endings, It also appears as PNS activates non-adrenergic, non-oholinerJgic inhibitory neurons to the IAS,

EFFECTS OF AN ENKEPHALINASE INHIBITOR ON ESOPHAGEAL MOTILITY IN MAN. S. Chaussade 7 R. Hamm, J.M. Leconte, O. Couturier, J. Guerre IRT et Service de Gastroent4rologie, HOpital Goehin, Paris, FRANCE. Enkephalins are short lived peptides wich are rapidly cleaved by 2 membrane peptidases : an enkephalinase and a carboxypeptidase. Enkephalin like immuno-resctivity has been demonstrated in the smooth muscle and in the myenteric plexus of the human Lower esophageal sphincter (LES). Opioid receptors have been found in the gastrointestinal tract and recently an enkephalin analog has been shown to inhibit LES relaxation (-18 %) and modify th@ peristaltic progression of the esophageal contractions (1). Acetorphan (2) is an enkephalinase inhibitor which prevents, at least to some extent, the hydrolysis of endogenous enkephalins. Thus, the present work was designed to study the effect of an enkephalisase inhibilor on esophageal motility in humans. Methods : lO healthy volunteers (mean age : 23 years) were studied. On 2 separate days, each subject received in random ordre acetorphan (2.5 mg/kg intravenously at a constant rate in 20 min) or placebo. Esophageal manometry was performed with a Oentsleeve. Wet swallows (5 ml) were performed at i min interval during 80 mSn and results were pooled in lO min periods. Results ; Acetorphan inhibits significantly ( p < O . 0 5 ) LES relaxation 20 min after the beginning of the infusion and throughout the study. The maximal effect ocoured 50 min after the beginning of acetorphan infusion and LES relaxation (m + SEN) was reduced from 92 2.6 to 79.5 + 2.9 % (p < 0 . 0 1 ~ . LES pressure increased slightly (p 7 0.08) 20 min after infusion of acetorphan (30.6 + 4.1 vs 25.5+ 4.5 cm H20). Duration, amplitude, velocity-of e s o p h a g e ~ contractions were not modified. Conclusion : Acetorphan an enkephalinasa inhibitor,is able to reproduce in human the effect of IV exogenous enkephalin on LES relaxation ; this result suggest that enGogenoua enkephalins might play a role in the normal control of the LES relaxation. * (i) JIAN and al, Gastroenterology, 1987 (in press) (2) ROQUES and el, Nature, 1980, 228, 286-288.

PLEXUSES OF NEURITES AND INTERSTITIAL CELLS OF CAJAL IN THE MAMMALIAN COLON: POSSIBLE GENERATORS OF RHYTHMIC ACTIVITY. J. Christenaen. Digestive Diseases Core Center, Univ. of Iowa Coil. of Mad., Iowa City, IA 52242 U.S.A. In the intestine, slow waves (SWs) arise in a plexus of neurites and interstitial cells of Cajal (ICCs) in the intermuscular plane. In the colon, SW arise at the circular muscle (CM)-suhmucosal surface, and rhythmic sinusoidal oscillations (myenteric plexus oscillations, MPOs) arise at the intermuscular plane. We examined whole colons of cats, dogs, ferrets, opossums, rabbits and rats, and fragments of human colons, stained by the osmic acidzinc iodide method (Champy-Maillat), in 25 pm serial tangential and cross-sections. The method stains neurites black, ICCs grey and other structures brown. Plexuses of neurites and ICCs were found at two planes. At the CMsubmuc0sal interface, complex branching of large cireumferantially-oriented ~pundlas of neurites formed a dense net of neurites in singlets and small bundles entangled with a dense mat of ICCs whose processes spread widely over the CM surface. The neurites originated from ganglia of Schabadasch's plexus. This plexus was similar at all levels of the colon and was present in all species examined except rabbit. It was not easily seen in crosssections. It was absent from the intestine. At the intermusaular plane, a similar plexus lay in the spaces outlined by the tertiary bundles of the myenteric plexus. This plexus was indistinguishable from that in the intestine. The plexus of nauritas add ICCs at the colonic CM-submueosal interface was first reported in rat and guinea-pig by Stach (Z. mikrosk-anat. Forsch, Leipzig 1972, 85:245). He named it the plexus externus extremns. Its composition, plane of location in the colon and absence in intestine support it as the source of colonic SWs. The plexus of nenrites and ICes in the intarmuscnlar plane may be the Source of colonic MPOs. (Supported by Research Grant AM34392 and Core Center Grant AM34982 from the NIH).

REGULATION OF SUBSTANCE P-b~DIATED NEUROTRANSMISSION AT THE MYENTERIC PLEXUS BY ADENINE NUCLEOSIDES. F.L. Christofi, T.J. McDonald and M.A. Cook. Departments of Pharmacology and Medicine, University of Western Ontario, London, Ontario, Canada, N6A 5CI. Regulation by adenosine of Ach release from enteric nerves is well established, as is the mediation of its actions by specific prejunctional receptors. T h e importance of peptidergic transmission in the enteric nervous system (ENS) required study of the role of the nucleoside in regulating such transmission and we report here evidence for the modulation by adenine nucleosides of substance P (SP)-mediated transmission at the ENS. Electrical field stimulatio n (ES, 20 Hz, 0.75 ms) or equieffective CCK-8 (5nM) were used to elicit SP-mediated contractions of the isolated longitudinal muscla-myenteric plexus preparation of the guinea-pig ileum in the presence of atropine ( 2 ~ M). These responses were ~ensitive tn0both TTX and the specific antagonist [D-prob,D-trp 7'9'I ] SP 4-11 (0.4 mM) while those to histamine and 5-HT were not. The responses to both CCK-8 and ES were inhibited by the adenosine A receptor agonist N6-cyalopentyl adenosine (CPA), by th$ mixed AI/A 2 agonist adenosine 5'-N-ethylcarhexamide (NECA) and by [he A9 agonist 2-phenylamino adenosine (2PAA). The rank-order el potency of these analogs against CCK-8 mediated responseswas CPA) NECA>>2PAA, consistent with the presence of A I receptors on nerves releasing SP. These data, togetNer with competitive antagonism of the inhibitory effects of nucleosides by the potent and specific A I antagonist 8-cyclopentyl theophyllina, provide clear evidence for the presence of functional adenosine A I receptors on myenteric paptidergie nerve endings. Interestingly, the order against ES was CPA=NECA>> 2PAA and the responses to NECA and 2PAA were biphasic, suggesting the presence of A 2 .receptors on an additional sub-populatiop of nerves releasing SP, or a related tachykinin, recruited by ES. Evidence for similar heterogeneity of adenosine receptors on cholinergic n e r v e s h a s been obtained and these parallel findings implicate adenosine in the widespread physiological regulation of transmitter release at the myenterir plexus. (Supported by MRC of Canada)

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Digestive Diseases and Sciences, Vol. 32, No. 8 (August 1987)

ABSTRACTS

OF

THE

ELEVENTH

INTERNATIONAL

~UT-SPECIFIC BETA-ADRENERGIC AGOHI3T5 INHIBIT R ~ T I~OLOH MOTILITY #I/,'tFR# FIND IHl,'Y//t?. ~ , Q. Bianchetti, E. Poq_ecl~], R. B o i o e o r a i n and ~ , Groupe 5QHOFI,Res'e-ar- ch Center-MIDY 5.p.R., i-,t~_n, rlCalp.

Beta-adrenoceptor aqonists are known to inhibit rat

Icolonic motili%, presumablybw actinq on beta and betap sites uJithin ~:he intestinal toall. Id~ ~ o u n d Chat, unllk~

typical beta-aqonists, compounds such as the follouJinq do not ~timulate qulnea-piq atrial, or tracheal adreBoceptors, but potently and-{electivelp inhibit rat colonic motility: ~R 58~I]16r (I), 2-[(?-h~d~o~p-l,2,5,~'tetrah~dronaphth-Z-ol)amino]- 1-phen~lethanol h~dro9chloride; 5R 58580fl "(11), 2 - [ ( ? - e ' t h o x b c a r b o n ~ l m e t h o x p 1,2,5,4-tetrahpdronaphth-2-t)l)amino]-'l -(5-chlorophenvl) ethanol o x a l 6 t e ; 5R 58218 (111), m e t h p l - i - [ 2 - ( ( 2 h);droxp-2-phenplethpl)amino)propgl]benzoale. In ~..itrc compounds'l, [I a n d III inhibi%ed r a t proximal colon spontaneous motilitv {IC~: Ox10-7, 4.?xi0-B and 3.5x10-7 H) and ~fl-dih~droalpren~o~ol bindinq to specific sites in

membranes or'eRare'cl from rat ~olon (IC~: 2.~xlD-e, 7.IxI0-~ and 1.6xlO-B M), with no chronS~ropic and relaxant action on quinea-Diq atrium or trachea up to 10 -5 M. Fiqures foF refer'en~ce beta-aqonists on "rat colon, quinda piq atrium and trachea ~ e ~ e : isoprenaline, 1.2x10~ , 2.BRID-s, I.?xi0-B ; salbutamol, 'B.BxlO-7, 2.:~xI0-~, 2.7x10-B; ritodrine, 4xi0-7, >lO-5,10-B./n ~'/*'~I,

SYMPOSIUM ON GASTROINTESTINAL MOTILITY DISTRIBUTION OF ENKEPHALINS IN THE DIGESTIVE TRACT OF THE CAT. A. CUPS, J.P. NIEL, J.P. MIOLAN, Y.JULE and T. JARRY. Centre d'immunologie de Luminy e% Dept. de Physiologie et Neurophysiotogie, Facu[t~ des Sciences de St J6r6me, Narseille - France. Only limited information is available concerning the quantifzcation and chemical characterization of enkephalins in prevertebral ganglia and regions of the digestive tract innervated by these ganglia. We performed radioimmunoaeeays for met- and Leu-enkephalin (ME and LE) in the coeliac and inferior mesenteric (IMG) ganglia as well as in the muscular and plexus layers of different areas of the digestive tract innervated by these ganglia. ME and LE contents increased gradually from the lower oesophageal sphincter (LOS) to the antrum, peaked at the pylorus and then decreased from the duodenum to the internal anal sphincter (IAS), The presence of ME and LE was confirmed in these tissues by high pressure liquid chromatography. Our results confirm the importance of ME and LE in the sympathetic and enteric innervation of the digestive tract. ~ sos. >

+.73

II, III a n d ritodrine inhibited proximal colon spontaneous motilit~ iv, e t h u l u r e t a n e anesthetized r a t s ~ith implan{ed strain "qauqes (ID:~: 0.62, 0.02, 0.12 and 0.2 m q / k q i.v.), an effBct T~reven~d b al renolol, I 5 m /k i.v2 b a t n o t

LE []

306 ~41

+-40

200-

148

b y propra~nolol, 2 m q f ~ ' q e i ~ . C o m p o u n d I~I, a sustained~> 5h) decrease of L3B in conscious r a t s c~ith chronicalI9 i m p l a n t e d

.~13

1130.

180 ~23

150

*.22

113

mg/kq p.o., c a u s e d frequ~encv

~0 285

~ 400-

83

42 ~lO

92 ~27

71~

,.,ir4 ele6trodes on t h e colon. Compounds I~11 hnd III

are prototvpes of a ne~ beta-adrenergic aqonists ~ i t h use

in p a t i ~ m t s

class of

prospective

~vith Irritable BoLvel 3 ~ m d r o m e .

gut-specific therapeutic

n=8 n=g ~=5 n=5 n=5 n=7 n=5 n=5 n=6 n=5

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n=8

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MECHANISMSDF GASTROESOPHAGEALREFLUX (GER) AND DISTAL ESOPHAGEALMOTILITY IN CHILDRENWITH GER DISEASE (GERD). S.Cucchiara, A.Staiano, C.Di Lorenzo, A,Della Rocca. Dept Clinical Pediatrics, II School of Medicine, Naples, Italy. We investigated the mechanisms of GER and esophageal mot i l i t y during endogenous esophageal acid exposure in 17 patients (p~s) with GERDalone (Apts)(range age: 3-18 months) and in 10 pts with GERDand esophagitis assessed by endosco py and histology (Bpts)(range age: 4-19 months), by simultaneous recording of distal esophageal m o t i l i t y and intraluminal pH. In A and B pts respectively, GER occurred by inappropriate lower esophageal sphincter (LES) relaxation (LESr)(37%; 62%; p
REINNERVATION OF A STRIATED HUSCLE BY VAGAL SENSOKYAY~NS IN THE SHEEP AI'~ PIG. A. Dalal, J.P. Laplace, O. Rampin and J.P. Rousseau. I.N.R.A., Laboratoire de Physiologie de la Nutrition, 78350 Jouy en Josas, France. Reinnervation of the sterno-cleido-mestoid (s.c.m.) muscle by sensory axons of the vagus nerve was previously performed in the sheep, rabbit and cat (Falempin and Rousseau, J. Physiol. (Lend.) 1983, 335:467 - goget and Rousseau, J. Physiol. (Loud.) 1983, 335-481). The peripheral stump of this nerve, eut above the nodose ganglion, was anastomosed with the peripheral end of the cut spinal accessory nerve which normally innervates the s.c.m, muscle. Afferents of the vagus, growing from cell bodies in the nodose ganglion, can replace the efferents of motor supply to the muscle. In the Sheep, additional experiments in 10 conscious animals showed that discharges of the sensory vagal neurones from the gut were recorded as bursts of electromyographic potentials occurring during oesophageal motility as well as in association with the motor cycle of forestomachs. In the Pig, similar experiments were performed in 13 growing animals. In anesthetized pigs~ evidence that there was reinnervation of the s.c.m, muscle by vagal afferent fibres was supported by the observations that electrical stimulations of the anastomosed cervical vagus nerve and of the superior laryngeal nerve elicited potentials in the s.c.m, muscle which were abolished by local anaesthesia or final section of the nerve proximal to the site of stimulation. Conduction velocities of reinnervating sensory fibres were within the range 6 to 10 m.s-1, In conscious pigs discharges recorded as bursts of electromyographic potentials were synchronous with lar)~geal and pharyngeal movements associated with respiratory movements or swallowing. Sheep are being used for more than one year while pigs, due to their growth rate, can not be used for periods longer 4 to 5 months, which do not allow extended reinnervation.

(A-S) Digestive Diseases and Sciences, Vol. 32, No S (August 1987)

907

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY THE ROLE OF MUSCARINIC RECEPTOR SUBTYPES IN TIlE CONTROL OF MIGRATING SPIKE COMPLEXES IN CAT. W.C, De Vos and C.L. Prosser. University of I l l i n o i s , Urbana IL 61801 USA l~e have previously found that propagation of migrating spike complexes (MSC) in the small i n t e s t i n e o f fasting cats is blocked by intra-abdominal hexamethonium (1-2mg/kg) or atropine (50~g/kg), suggesting the involvement of nicot i n i c and mugcarinic receptors in the mechanism of MSC propagafion. However, a dose o f atropine (lO~g/kg) below the i n h i b i t o r y threshold was found to s i g n i f i c a n t l y increase MSC frequency. The aim of the present study was to determine the role of M1 and M2 muscarinic receptor subtypes in the MSC. Each of f i v e cats was implanted with a set o f four bipolar electrodes at regular i n t e r v a l s from the proximal to distal ileum, and provided with a chronic femoral vein catheter. Recording sessions began following a 20-24 hour f a s t ; a drug or control saline was injected intravenously following the appearance o f an MSC at the oral electrode pair. Pirenzepine (PZ)(a selective H1 antagonist) at lpg/kg(n=7) never blocked an ongoing MSC, but did sign i f i c a n t l y increase MSC frequency. PZ at 75~g/kg(n=7) blocked the propagation o f an ongoing MSC and i n h i b i t e d MSC a c t i v i t y for a s i g n i f i c a n t period. Fol]owing t h i s i n h i b i t i o n , MSCs were s i g n i f i c a n t l y increased in frequency, and tended to occur in clusters~ McNeil A343 (a selective MI agonist) at 25(n=6) and 100(n=7) pg/kg had no s i g n i f i c a n t e f f e c t on HSC frequency, but at the higher dose consistentl y blocked an ongoing MSC. In the presence o f PZ (75pg/kg) t h i s i n h i b i t o r y e f f e c t was not observed. 4-DAMP (a select i v e I.l2 antagonist) at lO(n=6) and 50(n=6) pg/kg had no s i g n i f i c a n t e f f e c t on MSC frequency, but at the higher dose c o n s i s t e n t l y blocked an ongoing MSC. Conclusions: 1. MI antagonism by pirenzepine increases MSC Trequency, while MI stimulation by qc~leil A3r i n h i b i t s propagation of an ongoing !~SC, an action which is blocked by pirenzepine. These data suggest t h a t ~I receptors are not involved in MSC propagation, but are important in an i n h i b i t o r y pathway regulating MSC a c t i v i t y . 2. M2 antagonism by 4-DAMP blocks MSC propagation without a f f e c t i n g MSC frequency, suggesting the involvement o f M2 receptors in the propagation o f MSCs. A t e n t a t i v e neural c i r c u i t w i l l be presented.

NEURAL CONTROL OF THE CANINE GASTRIC MMC STUDIED BY COMBINING UNILATERAL VAGAL-PHRENIC NERVE SUTURE AND COLD BLOCKADE OF THE CERVICAL VAGI. N.E. Diamant J.P. Miolan, A.M. L ajard, C~ Roman. Department of Neurophysiology, University of Marseille, France, and Departments of Medicine and Physiology, University of Toronto. Studies in six chronic dogs were performed to assess: a) the potential for bilateral central control of the MMC via the vagi, and b) the effect of removing vagal sensory information (by vagal blockade), and removing the motor components of the MMC (by atropine and hexamethonium), on efferent vagal discharge to the stomach. Method: The vagosympathetic nerve trunks were previously isolated in skin loops on either side of the neck to permit blockade by cooling. Six months prior to study, the proximal end of the left vagus severed at the diaphragm, was sutured to the distal end of the severed left phrenic nerve. Efferent vagal discharge was recorded as the electromyogram of the reinnervated left diaphragm. Stomach and upper small bowel motor activity was monitored, and gastric vagal efferent fibers identified b y r e l a t i o n s h i p of their firing pattern to gastric motility. Results: I) Both right and left vagal fibers were found in the left vagus innervating the diaphragm. Left-sided fibers were more common than rightsided fibers. The firing pattern in fibers from both sides cycled with the gastric MMC. 2) Blockade of the right vagus decreased the duration and intensity of the MMC, and decreased the discharge of left vagal fibers during both quiescent and active phases of the MMC. 3) Blockade of the left vagus had little effect on either the MMC or the discharge of right vagal fibers. 4) Atropine abolished the gastric MMC, but vagal discharge continued to cycle with an MMC periodicity and with either equal or increased intensity. 4) With hexamethonium vagal discharge diminished and stopped cycling with a~ ~ C periodicity. Conclusions: Both ri~]t and left efferent vagal fibers participate in driving the gastric MMC. Functional efferent fibers crossover to enter the opposite vagus. Removal of sensory information markedly affects efferent . vagal discharge during the MMC. Occurrence of the gastric MMC with the intestinal MMC may depend on afferent messages from a peripheral neural mechanism.

908

INHIBITORY EFFECT OF THE ENKEPHALINASE INHIBITOR ACETORPHAN ON CASTOR-OIL INDUCED DIARRHEA IN MAN.E.D Dorva], E.H,Metman, J . M . L e c o m t e ~ , ..... J ~ B e r t r a n d ~ Gastroenterology, C.H.U. 37044 )Tours,and ~ Bioprojet 80, rue des F r a n c s B o u r g e o i s 75008, Paris FRANCE. Intestinal motor effects of exogenous opiates a r e well k n o w n . T h e a i m of our study was to f u r t h e r e x a m i n e t h e p o s s i b l e role of endogenous opiates using the peripheral enkephalinase inhibitor Acetorphan on a n experimental diarrhea inman. MATERIAL and METHOD:Five healthy volunteers (Om,2f)reoeived twice ,8 days apart, a 3 0 g l a x a t i v e d o s e of p u r e c a s t o r - o i l 45 min. afteP either Acetorphan (A),(II.9+/1.8 mg.kg-l,mean+/SEM) or P l a c e b o ( F ) given o r a l l y , b l i n d l y a n d in a r a n d o m o r d e r . O n s e t of the first stoo|(FS), total number (N)and w e i g h t (w)of s t o o l s w e r e assessed during the 24 n e x t h o u r s . RESULTS: (A) signifimantly reduced all parameters;(PS):7.0+/-O.Tvs4.0+/-0.7 Hours ; (N): 2.0+/-0.3 vs 3 . 4 + / - 0 . 2 ; ( W ) : 4 2 6 + / - 9 7 vs 7 1 2 + / - 6 0 g ( - ~ 2 % ) ; m e a n s +/- S E M , p < O . 0 2 . CONCLUS[ON:Peripheral emkephalinase inhibition, which acts through peripheral opiate receptors stimulation by endogenous opiates, demonstrates an antidiarrheal activity in this human experimental model.Further studies should focus on the possible clinical relevance of s u c h an a c t i o n .

ROLE OF THE SUBMUCOSA IN THE PROPAGATION OF COLONIC SLOW WAVES. C. Du and J.L. Conklin. Digestive Disease Core Center, Univ. of Iowa College of Medicine, Iowa City, IA 52242 U.S.A. Colonic slow waves (SW) are generated by pacemakers located at the junction between the submucosa a~d m u s c u laris propria. An intact submueosa is essential for SW generation. Our studies test the hypothesis that an intact submucosa is also required for SW propagation. The proximal colon of adult cats was opened lengthwise and pinned flat in a bath containing oxygenated Krebs solution at 37~ The mucosa was removed and electrical recordings were made with Ag-AgCI glass pore electrodes oriented along the long axis of the colon. After a 2 hour control period, recording continued from tissues exposed to TTX (ixl0- M) o r d i s s e c t e d in i of 4 ways. Dissections included: i) complete transection of the tissue between electrodes; 2) transection of the muscularis propria; 3) transection of the submucosa; or 4) removal of the submucosa from the midportion of the colonic segment. Tissues were stained by an osmic acid-zinc iodide method (Champy-Maillet) to determine the nature of tissues from which recordings were made. During control periods, all tissues generated SWs that propagated along the long axis of the colon. Complete transection interrupted SW propagation, allowing isolated segments to generate SWs at their intrinsic frequencies. Transection of the submucosa alone produced a similar result. Transection of the muscularis alone did not interrupt SW propagation. SWs could not he recorded from tissue segments devoid of submueosa. TTX decreased SW frequency, but did not interrupt SW propagation. The longitudinal propagation of colonic SWs does not occur through the muscularis propria alone. It depends upon an intact submucosa. SW generation and conduction are not neurogenic because they are not blocked by TTX. A plexus of interstitial cells present at the submucosamuscnlaris interface is a candidate for the conduction system. (Supported by Research Grants AM 34392, DK 01750 and Core Center Grant AM 34986, NIH).

(A-9) Digestive Diseases and Sciences, Vol. 32, No. 8 (August 1987)

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY E F F E C T S OF DIFFERENT NUTRIENTS ON SMALL BOWEL M O T I L I T Y IN MAN. P. D u c r o t t ~ r J.Y. T o u c h a i s r J. W e b e r , E. L e r e b o u r s t R. C o l i n , P . D e n i s .GBPDN U E R M ~ d e c i n e et C H U F 7 6 0 3 1 R O U E N C E D E X F R A N C E . We studied, in man, the effects on jejunal m o t i l i t y of a f a t t y or an a m i n o a c i d (AA) s u p p l y g i v e n i n t r a v e n o u s l y or by d u o d e n a l i n f u s i o n . Methods : Intraluminal jejunal pressures were continuously recorded from 2 p . m to 8 a . m the n e x t m o r n i n g f r o m s i d e h o l e s cut, iO c m apart, in an assembly of 4 catheters, the most proximal hole being l o c a t e d in t h e t h i r d d u o d e n u m d u r i n g the study. Volunteers remained fasting except d u r i n g the c a l o r i c s u p p l y c o n t i n u o u s l y d e l i v e r e d at a constant r a t e in a r a n d o m o r d e r f r o m 6 to ii p.m. The 10% fat infusion was given (iOOml/hour) intravenously (FIV), intraduoden o u s l y a l o n e (FID) or w i t h 20 g of c h o l e s t y r a m i ne (FID+C). AA s u p p l y (1.6 g of n i t r o g e n / h o u r ) w a s an i n t r a v e n c u s i n f u s i o n (AAIV) or a d u o d e n a l i n f u s i o n of s m a l l p e p t i d e s (SP) or of h i g h m o l e c u l a r w e i g h t p r o t e i n s (HM) w i t h the same AA c o m position. Incidence (number per hour) and char a c t e r i s t i c s f e a t u r e s of P h a s e s III ( P I I I ) , and the p e r c e n t a g e of the r e c o r d i n g t i m e o c c u p i e d b y the d i f f e r e n t motor patterns were determined b e f o r e , d u r i n g , a n d a f t e r the s u p p l y . Results : i) A s i g n i f i c a n t r e d u c t i o n of the inc i d e n c e of PIII and an i n c r e a s e of P h a s e s If, l e a d i n g to a fed m o t o r p a t t e r n w e r e s h o w n d u r i n g every duodenal infusion e x c e p t SP. 2) T h e same effect was d e m o n s t r a t e d d u r i n g the last 3 h o u r s of F I V but not d u r i n g AAIV. 3) In e a c h study, circadian variation of the characteristics f e a t u r e s of P I I I w a s shown. Conclusions : a) Changes in jejunal motility a p p e a r to be conditioned by the type of n u t r i e n t s , b) Changes induced by FIV have d e m o n s t r a t e d that the o c c u r e n c e of a f e d m o t o r p a t t e r n is n o t o n l y t h e c o n s e q u e n c e of a l u m i n a l phenomenon.

EFFECT8 OF VAGAL CRYO-INTERRUPTION ON COLON CONTRACTIONS M,J,Esser, J.C.Robinson, V.EoCowles, W.J.Schulte, J.J.Gleysteen, R.E.Condon. Department of Surgery, Medical College of Wisconsln, and Research Service, Zablocki VAMC, Milwaukee, WI, 53226 USA The vagus is thought to supply parasympathetic innervation (PSI) from stomach to mid colon, with PSI 0f the left colon (LC) supplied by sacral nerves. We have used the technique of reversible vagal cryminterruption (VCI) to explore the influence of vagal PSI on contractions of the colon in unanesthetized monkeys. Macaca arcteides were instrumented with strain gages on antrum (AN), right colon (RC), and distal LC. A cooling chamber was implanted around the thoracic vagi. Following recovery, vsgal integrity was confirmed by recording increased antral contractions in response to insulin induced hypoglycemia. The temperature required to abolish insulin induced antral contractions differed between monkeys; the specific denervation temperature (DT) for each animal was used in subsequent experiments. In the fasted state control activity was recorded for 60 min, VCI was then induced at the previously determined DT for 90 min, and the vagus then allowed to rewarm while recording for an additional 60 min. The feeding experiments were conducted in a similar manner with animals being fed after the control zecording~ cooled 38 min after feeding (a time at which the gastrocolic response is active), VCl maintained for 98 min followed by rewarming. Results: (mean contractions per i0 min ! SE;n=3) FASTING FEEDING Control VCI Recovery Control VCI Recovery AN 3.2+_1.0 0.4• 7.2• 6.0• 0.7• 10.2• RC 6.7+_0.6 0.7!0.3" 6.2• 6.9+_0.7 1.8• 6.9+_0.9 LC 8.9!0.8 0.6• !1.8!i.6 8.7!0.I 1.3• 10.5• *=P<0.05 compared to Control and Recovery. In both fed and fasted monkeys VCI reduced the frequency of colon contractions. Conclusion: Vagal PSl participates in regulation of colon contractions. Vagal PSI appears to extend further distally in the colon than has previously been demonstrated.

MINIMAL SAMPLING RATE REQUIRED IN AMBULATORY LONG-TERM pHMETRYo C.Emdeo P.Bauerfeind, R.Bumm~ AoLoBIum: Divisions of Gastroenterology, Kllnikum S t e g l i t z der F U ~ r l i n o WestGermany and OHUVo Lausanne, Switzerland. This study examined the influence of sampling rate on gastric a c i d i t y in long-term gastric pH-metry and on gastroeosphageal r e f l u x in esophageal pH-metryo Ultrafrequent pH-recordings (256 aamples/min) were obtained from the esophagus and stomach of healthy volunteers using a microprocessor-equipped programmable ambulatory long-term pH-recorder (LZ-I05, Kaufhold, West-Germany) and glass electrodes (440-M4o Ingold, Switzerland~ response time about I sec)~ Measurements were started at 10 aom~ and had a duration of 8 hours resulting in a t o t a l of 122880 pH-valueso D i f f e r e n t measuring conditions were created by administering a standardized meal at 12 a:m: and an H~-antagonist at 2 p.mo Original recordings as well as reduce~ versions of the recordings (considering every 2nd: 4th, 8th etc sample) were evaluated f o r gastric pH-median, esophageal r e f l u x time (percentage of time with pH below 4) and number of detected gastro-esophageal r e f l u x episodes (GERE)o Gastric pH-medians were not influenced by sampling ~ate in the range from 256 to I/mino Esophageal r e f l u x data VSo sampling rate are given in the table:

CAN TRANSCUTANEOUS ELECTRODES DIAGNOSE GASTRIC ELECTRICAL ABNORMALITIES? B.O. Familoni, K.L. Bowes~ Y-Ju Kingma and K.R. Cote. Departments of Surgery and Electrical Engineering. University of Alberta, Edmonton, Alberta, Canada. Transcutaneous techniques for measuring gastric electrical activity (GEA) have been advocated as a diagnostic technique. We have studied how accurately this noninvasive technique detects both regular az~d irregular GEA as recorded by implanted electrodes in post-operative patients. Three sets of bipolar stainless steel electrodes were implanted into the antral wall of 6 patients at laparotomy. GEA was monitored continuously for 4 days from the implanted electrodes and 2 pairs of extracoporal electrodes located in the epigastrio region. The data was digitized and stored on an IBM personal computer and analysed visually, by sequential power spectral analyses over successive 128s intervals and by signal enhancement with an adaptive filtering technique. We were able to recognise GEA on the serosal recordings in 484.64 hours out of a total recording duration of 491.9 hours. SW were recognised at the cutaneous record in 465.36 hours and correlated with the serosal signal in 458.6 hours. 156 and 144 separate episodes of irregularities in GEA were seen at the serosal and cutaneous electrodes respectively and 136 of these occurred simultaneously. For those segments in agreement, the mean percentage difference in SW period was 0.83% + 5.45%. The SW frequency evaluated by power spectral analyses were the same for Both methods 95.71% of the time. The adaptively filtered transcutaneous signal showed a better agreement with the serosal record in both number of irregular episodes denected and correlation of the SW frequency. Transeutaneous GEA recordings accurately reflect both regular and irregular GEA.

samples/m!n 256 128 64 32 16 8 4 2 I r e f l u x time 6.5 6~ 6~4 6~ 6o4 6.4 6~ 6.9" 7~ GERE/8 h 20 20 20 17" 15" 12" 11" 9* 6* (*p<.OB) I t is concluded that esophageal r e f l u x time and gastric pH-medLans are independent from sampling rate down to a value of 4/min. The q u a n t i t a t i v e detection of GERE~ however~ largely depends on sampling rate. The necessary sampling rate is f a s t e r than normally available in commercial systems~ This fact may explain why "normal values" of GERE d i f f e r between d i f f e r e n t centers~ Furthermore: in each organ and f o r each variable measured by ambulatory long-term pHmetry a specific minimal required sampling rate exists which must be determined when appropriate measuring conditions are to be defined~ (Supported by SNF 3~176176 and DFG Em 36/I-3)

(A-IO) Digestive Diseases and Sciences, Vol. 32, No 8 (August 1987)

909

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY ULTRASTRUCTURE OF THE INTERSTITIAL CELLS OF CAJAL AND NERVE ENDINGS IN PACEMAKER AND NON-PACEMAKER AREAS OF HUMAN STOMACH. M.S. Faussene-Pellegrini~ Pantalone*,C. Cortesini*.~ Human Anatomy and Hystology,*Institute Surgical Pathology,University of Florence,Florence,Italy. The circular muscle layer of the corpus obtained from the stomach of 5 patients operated on for antral carcinoma (early stage) and whose motility could he considered as normal,was examined electron microscopically to see if there were structural" differnces between pacemaker and nonpacemaker zones. Compared to those of other levels of the gut,this muscle layer in all the examined areas showed several peculiarities,some of which were similar to these already described in human LES.Differences in the number, location and structure of interstitial cells and nerve endings were found in the gastric areas. The main differences were found between the greater curvature(usually considered as the gastric pacemaker zone)and the other areas. In this zone the interstitial cells are mostly located at the periphery of the muscle bundles and are similar to smooth muscle cells being richer in filaments and endoplasmic reticulum than in the other areas.Most of the nerve endings in the pacemaker areas contain large granular vesicles and are mainly close to the interstitial cells.On the contrary, in the other areas the nerve endings are more numerous,often contain a mixture of synaptic vesicles and most of them are also near and in close contact with smooth muscle cells. These findings seem to indicate that the nerves mainly control the interstitial cell function rather than the smooth muscle of the pacemaker area.%n the other zones smooth muscle in also under intensive nerve control.These data can be related to the differences i n t h e motility among the gastric areas examined and may help to explain the role played by the interstitial cells of Cajal.

INVOLVEMENT OF ENDOGENOUS OPIATES IN THE REGULATION OF GASTRIC EMPTYING OF FAT MEALS IN MICE. J. Fioramonti, M.J. Fargeas and L. Bunco, Department of Pharmacology, INRA, Toulouse, France. Background : Opicid peptides are known to inhibit gastric emptying and the presence of an enkephalin-like immunoreactivity in myentetic plexus suggests a physiological enkephalinergie control of gastric emptying. However blockade of opiate receptors hy naloxone does not modify gastric emptying but these data were obtained with meals containing no or few nutrients. Aims of study : This study was undertaken to determine the role of nutrients in the regulation of gastric emptying by endogenous opiates. Material and Methods : Gastric emptying of different 0.5 ml liquid test meal (cow milk or I00 mg arabic gum + several food constituants) containing 0.5 pCi of Na2SICrO~ was measured in mice killed 30 min after garage and receiving s.c. 0.25 ml of saline (control) or naloxone (0.i mg/kg), i0 min before garage. Gastric emptying of milk was also measured after s.c. (0.I mg/kg) or i.c.v. (i0 ~g/kg) methyl ievallorphan, a narcotic antagonist with peripheral selectivity. Results : Gastric emptying (% 51Cr) of different test meals ..................... _ ..................................... Test meal i 2 3 4 5 6 ........................................................... Control

33.9 35.1 36.6 31.3 45.2 46.3 • • • • • 61.1" 39.8 61.3" 63.2* 37.3 77.1" • 9.5 • 8.5 • 6.1 • 9.8 • 8.9 • 7.0 ____~........................................................

•

Naloxone

1 : Milk, 2 : Glucose 500 mE, 3 : Arachis oii 250 pl, 4 : Glucose 125 mg Oil 60 ~I, 5 : Casein 180 mg Glucose 125 mE, 6 : Casein 120 mg Oil 60 ~i. * : P < 0.05, n = 6. Maloxone only accelerated gastric emptying of meals containing lipide. Gastric empyting of milk was accelerated after s.c. but not i.c.v, administration of methyl levallorphan. Conclusions : These results indicate that endogenous opiates are involved at peripheral level in the regulation of gastric empyting of fat meals only. The release of CCE by fat and the interactions between CCK and opiates, suggest a role of CCK in this opioid regulation.

NEUROTENSIN AND THE CANINE SMALL INTESTINE 1, CIRCULAR MUSCLE (CM) MOTILITY IN u AND TM u J~E.T. Fox r F. Kostolanska, H.D. Allesoher and E.E. Daniel. Smooth Muscle Program, McMaster University, Hamilton, Oct, Canada. Im v t w o close intraarterial (IA) neurotensln (NT) inhibited intestinal phasic activity occurring spontaneously or induced by local field simulation of nerves by release of norepinephrine aL low doses and a direct smooth muscle action at higher doses. Activity was not stimulated by IA NT during quieseeaence (Can. J.Physiol. Pharmacol.t98~,62,403). If ACH IA at ~ min intervals was used as the submaximal excitatory stimulus, NT 2G see before ACH caused a delayed increase in the ACH response (~o-Itmol) o r immediate inhibition (I0-9moi). In contrast in wltro full thickness (LM+CM) strips suspended to r e c o r d CM activity responded to NT w i t h an i n c r e a s e in a m p l i t u d e and frequency of contractions at 10-11M and Inhibition followed by a tonic contraction a% I0-7M. The phasic responses to NTIO-I~M of LM+CM strips were unchanged by TTX or Indomethacin but inhibited reversibly by 5,8,11,14-eicosatetraynoic a c i d or Ca2+-free incubation suggesting that phasic aoZivlty resulted from release of s llpoxygenase metabollte and that extracellular Ca 2+ was required either for contraction or metabolize formation. Strips were dlssecbed to contain; a) the deep muscular plexus (DLP) and adjacent muscle only, b) the remaining CM and LM or c) CM with only LM and the myenterie plexus removed and studied in a clreular orientation. Only strips containing DLP responded with phasic activity at I0-11M HT but all strips showed inhibition and the tonic contraction at NTI0-7M. In the DLP strip, rapid (17-20/min) phasic contractions, not seen in other preparations, w e r e superimposed on the tonic contraction which followed inhibition at I0-7M. Thus the receptors for NT which produce inhibition are present in all regions of CM but receptors for phasic excitation are located on g M e e l l s near the DLP. We suggest that Im Yiwo excitation by exogenous ACH rather than by ACH released by field stimulation optimizes the participation of these cells in the contraction. Supported by the MRC, Canada and DFG, West Germany.

MYOELECTRIC AND CONTRACTILE ACTIVITY INTRINSICALLY DENERVATED SMALL BOWEL

OF

C.T. Frantzides, R. E. Condon, J. Garancis, 8. Doumas. Medical College of Wisconsin, Department of Surgery, 8700 West Wisconsin Avenue, Milwaukee, Wisconsin 53226 U.S.A. The aims of this study were to induce degeneration of the intrinsic nerves of the small intestine and to study the effects of intrinsic denervation on the myoelectr/e and motor activity, Four dogs were instrumented w i t h six bipolar electrodes and two electrod-strain gauge p a i r s . Fasting myoelectrical and motor activities were recorded from the small bowel (8hrs/day) for up to 20 days. At least two consecutive control MMC cycles were recorded each day. Premature MMC's were induced by motilin (0.2pg/kg, IV) or morphine (100}~g/kg i.v.). O n c e control experiments were completed the animals were reoperated and a 15 cm segment of jejunum was perfused (close intra-arterially) with a 1.5% solution of neurotoxic cobalt chloride (100 ml). Subsequently to the 5th postoperative day, the cobalt-treated segment (CTS) had irregular SW's with variable frequencies and low amplitude. The SW frequency eaudad to the CTS was reduced. SB's and their associated contractions in the CTS were of longer duration and of lower frequency compared to the control tracings. Spontaneous MMC's cycled normally in the small intestine. Phase III activity, traversed but did not occur in the CTS. The timing of the occurrence of phase Ill caudad to the CTS was identical to the one obtained in control recordings. Morphine (100 ~g/kg, IV) initiated two independent premature MMCts; one in the duodenum and another (ectopic) just distal to the CTS. Bethaneehol (25 Bg/kg, IV) initiated SB's in the entire small intestine including the CTS. All animals were sacrificed one month later, Electron microscopic and immunohistochemicalexamination of the CTS revealed complete destruction of gaglion cells and axons, and disappearance of substance P, VIP, and met-enkephalin immunoreactivity in both the myenteric and submucosal plexuses. Smooth muscle and mucosa showed no abnormalities. We conclude: I) CoCl2 causes chronic degeneration of enteric neurons. 2) The denervated segment does not exhibit phase III activity. 3) Denervation does not interrupt phase III migration. 4) Stimulation by morphine initiates ectopic MMC. Supported by NIH grant I-R29-DK38486-01.

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY EFFECTS OF SENMOSIDES ON HUMAN COhONIC MYOEbECTRICAL ACTIVITY. J. Frexinos, G. Stau@ont, J. Fioramonti and L~. Bu~no. Department Of Gastroenterology Rangueil ~ospital and Department of Pharmacology INRA, Toulouse, France. Background : Sennosides are useful anthraquinonie laxatives with an elective colonic tropism. The mechanisms of secretory effects seem now well understood, but the effects on motility are still discussed. In man a stimulation of peristaltism or a decrease of intraluminal pressure after sennosides administration has been reported. Similarly, a hypo or a hylpermotility has been shown in animals. Aims of study : This ~tudy was undertaken to investigate the effects of oral administration of sennosides on the human colonic myoelectrical activity. Material and Methods : Myoelectrical activity of the left and sigmoid colon was recorded with an intraluminal probe 0.5 cm in diameter and 70 cm in length, supporting 8 groups of B annular electrodes in 7 IBS patients without diarrhoea. Bipolar recordings were made with a 8 channels electroehcephalograph. The probe was introduced by colonoscopy, in the morning without major bowel cleansing, allowing metabolism of sennosides hy microorganisms. The recording session, lasting 36 hours, began the same day at 5.00 pm. Meals were given at noon and at 6.30 pm. The patients received at 7.00 pm, either 30 mg of sennosides, either placebo in a prospective double blind cross over trial. Results : Each subject presented the two kinds of spike bursts (SSB and LSB) already described. After placebo, migrating LSB (MLSB) ahorally propagated over the 8 electrode sites appeared mainly after the meal and a very low LSE activity was observed during the nighttime. After sennosides administration a strong increase in the frequency of MLSB appeare d between midnight and 7.00 am. A slight but significant (P < 0.05) increase in the number of LSB localizedl at one electrode site or propagated over few centimeters, but no modification in the $SB activity was detected. Conclusions : These results indicate that the main modification of colonic motility by sennosides is an increase in propfilsive activity (MLSB) which app@ars 5 to 7 hrs after oral@dministration, a time which corresponds to orocaecal transit and metabolism of the drug.

CEREBRAL RESPONSES EVOKED BY ELECTRICAL STIMULATION OF THE RECTOSIOMOID IN NORMAL SUBJECTS. I= Es ~• ~n~kz

~E~hl• rology*,

~=

Wi@oh~k

.Depts. of Gastroenterology

and Neu-

U n i v e r s i t y of OOsse]dor~, F. R. Germeny Evoked p o t e n t i e l s (EPs) in response to e l e c t r i c a l s t i mulation of e i t h e r the u r i n a r y bladder or fhe v e s i c o urethral juncfion h e v e r e c e n t l y been reported (Electroencephalogr Clin Neurophysiol 1986: 65: 440). We, t h e r e fore set out to look for cerebral responses t o e l e c t r i c a l s t i m u l a t i o n of the rectosigmoid colon in 8 healthy male volunteers~ 20-40 y e a r s old, The stimulus was applied v i a a probe equipped with bipolsrring electrodes w h i c h were

sucked to the mucoea. The probe was positioned the anus. The e l e c t r i c a l s t i m u l i lasted 0 . I

20 cm above

m s e c . They were applied at e frequency of 3 Hz. Voltage was i n creased, unfil the volunteers perceived a non-painful sensation. Cerebral responses were recorded from the v e r tex (Cz) by EEG electrodes. They were averaged over 1505D0 sweeps. The reference electrode Was alteched to the forehead (Fz). At least 10 t r a n s i t s were taken from eech volunteer in order to evaluafe p o s i t i v e (P) end negative (N) d e f l e c t i o n s of EPs. Lstencies (msec) 0s EPs Onset P1 N1 Pg N2 Mean 57.6 72.6 96.5 132.4 152.0 SD 7.6 8.8 11.7 10.6 I0,6

0nset/Pl

Amplitudes (uV) of EPs PI/NI NI/P2 P2/N2

Mean

0.7

0.9

0.9

0.7

SD

0.2

0.2

0.4

0.2

The s h a p e and l e t e n c i e s of the i n t e s t i n a l EPs were Comparable to other types of EPs reported before. It is concluded that reproducible EPs can be recorded from the scelp a f t e r e l e c t r i c a l s t i m u l a t i o n of the reciosigmoid. The s i m i l a r i t y in appearance of these EPs %o those prev i o u s l y reported suggests that v i s c e r a l s f f e r e n f s were stimulated. The technique may be useful in the detection of v i s C e r a l n e u r o p s t h y .

Digestive Diseases and Sciences, Vol. 32, No 8 (August 1987)

DIFFERENTIAL EFFECTS OF CLOSTRIDIUM DIFFICILE TOXINS A AND B ON INTESTINAl SMOOTH MUSCLE. R.J. Gilbert. G. Triadafil)poulos, C. Pothoulakis, J.T. LaMont. Section of Gastroenterology, University Hospital, Boston, MA 02118 USA C. difficile enterotoxin (TxA) mediates the inflammatory changes of colitis, whereas cytotoxin (TxB) causes disagg regation of actin filaments in cultured smooth muscle. In this study we compared the functional effects of toxins A and B on intestinal smooth muscle, and correlated these effects with intestinal permeability and morphology, METHODS: Purified rxA and TxB were siren either in vivo in isolated rabbit ileal loops (60 ug/ml for 2 hrs) followed by muscle strip excision, or in vitro (4-60 ug/ml). Circular smooth muscle was studied by simultaneous measurements of intracellular membrane potential and tension. Permeability was assessed i~ vivo as intestinal clearance of IV 3H-mannitol. RESULTS: Exposure of rabbit ileal loops co TxA resulted in mucosal inflarmnation and an 8-fold increase in blood-lumen clearance of 3H-mannitol, whereas TxB caused no effect on permeability ox morphology. TxA, given in vivo, caused membrane depolarization, augmentation of carbachol (10-7M)-in duced phasic contractions (PC), and inhibition of tonic con L tractions (TC), while Txg caused no significant effect on electromechanical properties (Table), (*p
INHIBITION OF PROSTAGLANDIN SYNTHESIS PROTECTS THE IRRADIATED INTESTINE. ~.E. Glenn and R.W. Stummers. Center for Digestive Diseases, Veterans Administration Medical Center and University of Iowa, Iowa City, Iowa 52242, USA. Abdominal irradiation acutely produces nausea, vomiting and dysentery, suggesting disordered motility. Previous studies suggest that irradiation increases intestinal prostaglandin (PG) synthesis and exogenous PG's profoundly affect both neural and smooth muscle activity. The purpose of the study was to investigate the motility effects of indomethacin (IN) before and after irradiation. Motility was monitored from electrodes sutured to the proximal jejunum in 3 groups of 6 dogs: non-irradiated controls and irradiated dogs with and without IN therapy. Following baseline studies, an x-ray generator delivered 1250 R to the abdomen. One group received IN 5 mg/kg q 12 h, beginning 3 d before and continuing for 4 d after irradiation. On day 4 messnteric arterial and venous blood was collected i n E D T A and IN-treated tubes and jejunal tissue specimens were fixed for histologic study. Plasma was analyzed by RIA for POE2, PGF2~ and 6-keto PGFI~. Myoelectric Activit% Controls 1250 R 1250 R + IN Normal slow waves 6/6 0/6 * 3/5 Migrating motor complex 6/6 0/6 * 5/5 Spike burst/min 8.4 2.5 * 7.2 Spike burst duration (see) 0.42 0.14 * 0.65 Venous [PG]-arterial [PO) PGE 2 (pg/ml) 84 1784" 221 PGF2e (pg/ml) 23 356* 40 6-keto FI~ (pg/ml) 339 8454* 419 * p < O 05 compared with non-irradiated controls Radiation increased intestinal PC's; IN inhibited this increase and had a protective effect. IN treated dogs exhibited: I) reduced symptoms of irradiation enteritis, 2) less mucosal injury, 3) lower concentration of plasma PG's and 4) fewer changes in myoeleetric activity compared With untreated dogs. We conclude that PG's play an a d v e r s e r o l e in the intestine after irradiation, intensifying structural and motor abnormalities. This study supports the iruhibition of PO synthesis in reducing injury to the gut from irradiation. Supported by VA Research Funds and NIH grant AM34986.

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY I~URO~ISTOCHEMICALSTUDYOF THE ENTERIC NERvOusSYSTEM AT THE ILEOCECAL JUNCTION. P.G. Goetst~uwers, P.A. Pelckmans, P. Cras, Y.M. Van MaercKe, ~. ~uy~sens. Unlvers~ty ot Antwerp {UIAI, B~vis~ons of Gastroenterology and Pathology, B-2610 Antwerpen-Wilrijk, Belgium. A comparative study of the enteric nervous system (ENS) at the ileocecal junction (ICJ) has been performed in several mammals and man. Staining of the intramuraT nerves was done by two immunohistochemical techniques. An antiserum against neuronspecific enolase (NSE) stained the neurons and the axons, wh~le an antiserum against S-lO0 (soluble protein) stained the Schwann cells and their ramifications. The structure of the myenterlc and the submucosal plexuses at the ICJ'~as consistent i~ all species. The myenteric plexus shows large sized ganglions. The fibers which leav'~-T6"t-~eganglions always end in the c i r cula~ ~uscle l a y e r . The core of the ICJ i s g e n e r a l l y composed of the c i r c u l a r muscle layers of ileum and colon and the myenteric ganglions &re l o c a l i z e d along the septum between them. At the base of the ICJ, more and larger ganglions are found than in distant sites. The submucosal plexus has ganglions of a s m a l l e r size; they are ~rregularly scattered throughout the submucosa, but more concentrated toward the lamina muscUlaris mucosae. NO change in number or size is found at the ICJ. Nerve fibers from the submucosal plexus are directed toward the lamina muscularis mucosae, which they pener trate, forming a diffuse network in the lamina propria around the glandular crypts. Our data show a distinct structure of the ENS at the base of the ICJ, characterized by the presence of more and larger ganglions in the myenteric plexus.

INFLUENCE OF DIGESTA COMPOSITION ON ABOMASAL OUTFLOW IN SHEEP. P. C. O ~ & S- J. Miller, Rowett Research Institute, Bucksburn, Aberdeen, Scotlahd AB2 9SB Abomasal emptying in pre-ruminant calves is subject to similar feedback control mechanisms from the duodenum to those seen with gastric emptying in monogastric animalsJ We have investigated the influence df duodenal composition on outflow from the abomasum in adult sheep, ~n w h i c h wide variations in flaw during the day have been reported. s outflow rate was detebmined from the rate of dilution of CrEDTA in the abomasum (Br.J.Nutri1985! 53, 373). With sheep fed 750 g grass cubes twice daily, and hourly measurements made during phase II of the MMC there were no significant changes in abomasal volume or eutflow rate between 2 and 7 h after feeding. Comparing the mean measurements taken during duodenal infusion (5 ml/min) at 4-7 h after feeding with those before infusion of 1OO mM lactic, acetic, propionic and butyric acids, KCI, 2% and 4% peptone and 10% glucose3 abomasal outflow was reduced by 40• (P
THE ROLE OF PROSTAGLANDINS IN THE CONTROL OF GASTRIC MOTILITY - COMPARATIV E STUDIES 1N ISOLATED GASTRIC MUSCLE FROM MAN, DOG AND PIG K. Golenhofen~ K. Mandrek~ U. Beaupain~ P. 3ochem add. F.E. LUdtke* . Department of Physiology, D'3550 Marburg/Lahn, FRG; *Department of General Surgery, D.3#00 G/Sttingen, FRG. Comparative studies in human, c a n i n e and porcine gastric smooth-muscle have shown t h a t in several aspects porcine stomach is the b e t t e r model for human stomach than canine stomach (G61enho*en et ak, Pgltigers Arch. ~ Suppl., R 42, 1996). This has how been tested for the prostaglandin-related mechanisms. We dissected longitudinal (1o) and circular (ci) strips from fuhdus (Fu), corpus (Co), antrum (An) and duodenum, and circular muscle from the i n n e r and outer layers of the pyloric sphincter (Py.inn and Py-out). The mechanical activity of these muscle preparations was recorded simultaneously under auxotonic conditions. The general rule t h a t PGF2E stimulates longitudinal as well as circular muscle, whereas the PGEs stimu!ate longitudinal and inhibit circular muscle, is valid for most types of preparation from all species. Exceptions: The excitatory e l . / e c t of PGF2c~ b negligible in antrum and pylorus ; the PGEs have an excitatory e f f e c t also on Fu-ci, and sometimes inhibited a c e tyIcholine-stimulated porcine An-lo. The most interesting observations are the species differences in the Py-inn responses. In canine Py-inn, arachidonic acid (10<5 tool/l) inhibited' the spontaneous activity, and indomethacin (10 -6 tool/l) strongly increased the spontaneous activity, indicating a pqtent endogenous synthesis of an inhibitory prostaglandin (Milenov and Golenhofen, Drostaglandins, Leukotr. Medo 8, 287-300, 1982). In porcine P.y-inn, in contrast, excitatory effgcts of indomethacin were never observed, sometimes inhibitory effects were seen, and arachidonic acid increased the pylorus activity; The endogenous prQstaglandin synthesis seems to be less pronounced in porcine than in canine py-inn. In this respect human Py-inn is similar to porcine Py-inn. In most preparations from l0 human stomachs indomethacin had no significant e f f e c t on Py-inn, and only occasionally the spontaneous activity o~ this preparation was slightly i~creased.

CONTRACTILE PROPERTIES OF CULTURED HUMAN INTESTINAL SMOOTH MUSCLE CELLS. J.R. Grider, H.A. Per F, M.F. Graham, and G.M. Makhlouf. ---Medical College of V i r g i n i a , R i c ~ V A . - - We h a v e r e c e n t l y shown that cultured human i n t e s t i n a l smooth musQl@ cells retain t h e i r morphological Characteri s t i c s . We have 9ow developed methods to examine t h e i r functional charact@ristics. After 2-4 passages, muscle cells were dispersed and regrown on glass coverslips f o r 3-5 days. The Coverslips were pbsitio~ed so as to form the ceiling of a perfusion chamber (0.1 cm ) and perfused i t the rate of l ml/min with HEPESmedium. The lengths Of 2-4 cells at the edge of each culture were measured continuous~ ly by scanning micrometry. In the control state, cultured smooth muscle cells exhibited slow, phasic c o n t r a c t i o n s with a frequency of 0.5/mi n and an amplitude of 15-20% ef maximal agonistlinduced tonic contraction. Perfusion with c o n t r a c t i l e agonists (CCK-8 l pM and l nM, dynorphin-13 l uM, acetylcholine 10 pM and l uM) e l i c i t e d a prompt concentration-dependent tonic contraction which rose to a peak in 1.5 min before reverting to a sustained lower p l a t e a u . Maximal contraction induced by l nM CCK-8 (27.9• decrease in cell length from c o n t r o l ) , l uM dynorphin-13 (24.7• and l uM acetylCholine (28.1• was similar to that in freshly isolated human jejunal smooth muscle cells (26• The response of cultured c i r c u l a r cells to CCK-8, like that of freshly i s o l a t ~ c i r c u l a r c e l l s , was not affected by addition of the Ca~- channe~ b l o c k e r , methoxyverapamil, whereas the respon~ to K I20 mM) ~as inhibited by 70% Cytosolie free ca was measured a f t e r loading the coverslip cultdre with quin2/AM foe 60 min. The coverslip was then placed in a cuvette designed for continuous perfusion. Addition of CCK-8 (l n ~ caused a prompt 2.5 fold increase in cytosolic free Ca" - , i . e . , to the same extent as in freshly isolated c i r c u l a r human muscle c e i l s . In conclusion: human i n t e s t i n a l muscle cell cultures retain the functional properties of f r e s h l y i s o l a ted muscle c e l l s , including the a b i l i t y to respond in a concentration-dependent manner to c o n t r a c t i l e agonists. Cells derived from the c i r c u l a r musg~e layer retain the a b i l i t y to release i n t r a c e l l u l a r Ca~ . The cultures provide the opportunity to examine myogenic phasic a c t i v i t y .

912

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Digestive Diseases and Sciences, Vol. 32, No. 8 (August 1987)

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY CNS-BLOCKADE OF ACOUSTIC STRESS INDUCED GASTRIC MOTOR INHIBITION BY KAPPA OPIOID AGONISTS IN CONSCIOUS DOGS. N. Gu@, C. Hond~*t X. Pascaud*, J.L. Junien*, R. Alvinerie and L. Bu~no. Department of Pharmacology INRA, 31300 Toulouse, France and *Jouveinal Laberatoires, 94260 Fresnes, France. Central release of oorticotrepin releasing factor (CRF) seems involved in the genesis of stress-induced gastrointestinal motor alterations and opioid peptides are able to inhibit ACTH and cortisol secretion. Consequently this work has been performed to compare the influence of centrally administered ~appa (dynorphin1-,a and ethylketoeyclazoeine) and mu (DAG0) opioid substances on gastric moth• inhibition in~uced by acoustic stress (A.S.) in fasted dogs fitted with chronically strain-gauge transducers implanted on the antrum and proximal jejunum. A.$. was Obtained by the hearing of music through ca• (< 90 dB) inserted into the ears. Started 40-50 min after the last gastric MMC, A.S. (one hour) delayed by 114 % the occurrence of the'next gastric MMC while the intestinal motility was unaffected. During A~S. ~lasma eor~isol was significantly (P < 0.05) increased by 215 %, 15 minafte• the beginning of hearing. When administered ICV at doses of 20 and ~0 ng/kg dynorphin reduced or abolished respectively the A.S. induced lengthening of the gastric MMC cycle. Similar blockade was observed for EKC at dqses of i0 and 20 ng/kg while DAGO was nnabl~ to affect the A.S. induced gastric inhibition at the doses tested (20-200 ng/kg ICV). All these substances were unable to affect basal plasma eortisol level or oortisol release induced by IV ACTH (5 UI) when administered alone. At doses active against A.S~ induced hypomotility, both ICV dynorphin1-1s (i00 ng/kg) and EKC (20 ug/kg) strongly reduced by 43 to 87 % the associa%ed maximal increase in plasma eortisol level which was not modified by previous ICY administration of DAGO. It is Concluded that kappa hut not mu sabstances act centrally to Suppress the inhibition of gastric motility and the plasma eortisol increase prodaee~ by A.$. probably by the blockade of stress-induced CR F release.

MODULATION OF CHOLECYSTOKININ RECEPTOR ON ISOLATED GASTRIC SMOOTHMUSCLE CELLS BY ACETYLCHOLINE: MEDIATION VIA RECEPTOR AND POSTRECEPTORMECHANISM. W. Hasler and C. Owyang. Dept. of Internal Medicine, The U n i v e r s i t y of ~gan, Ann Arbor, MI 48109 U.S.A. Cholecystokinin (CCK) and acetylcholine (ACh) are potent stimulants of gastric smooth muscle contraction. Although separate CCK and musearinic receptors have been i d e n t i f i e d on gastric smooth muscle c e l l s , both u t i l i z e a common Ca++- phosphoinositide mediated postreceptor coupling mechanism. This study evaluated the modulation of gastric smooth muscle CCK receptors by ACh and investigated the mechanisms involved. Isolated smooth muscle cells were prepared by cpllagenase digestion o# guig~a pig stomach and were stimulated with ccK8 (10 -• lO-~UM). Contractile response was measured as percent decrease in cell length. CCK8 stimulated contraction of isolated gastric s ~ o t h muscle cells in a dose related manner (EDmn=3XIO~ M). Preincubation with ACh (IO-/M) reduced CCK~ (IO-ILM) stimulated response by 49• This was reversed by addition of H7 ( I 0 - M), a protein kinase C inhibitor. Similar i n h i b i t i o n of CCK8 induced c o n t r a c t i l e response was observed with pretreatment with atropine (5xlO-~ This was however not reversed by H7 suggesting ACh i n h i b i t s muscle response to CCK by a receptor and postreceptor mechanism. To c l a r i f y the postreceptor mechanism involved, cells were preincu~ated with 12-O-tetradeeanoylphorbol 13 acetate (TPA, IO-~M), an a c t i v a t o r of protein kinase C. This resulted in a decrease in CCK-induced muscle ~ontraction from 14.9• to 7.3• Addition of H7 (IO-'M) completely reversed the TPA induced i n h i b i t i o n . 7 In p a r a l l e l s } u d i e s ~ i n e u b a t i o n with ACh (IO- M) or TPA ( I 0 - M) reduced I-CCK8 binding by 27.6f4% and 24.1• respectively. In contrast VIP, which operates through a cAMP mediated pathway, had no e f f e c t on ~ I - C C K 8 binding. In conclusion we have shown that ACh decreases CCK stimulated smooth muscle cell contraction by a receptor and postreeeptor mechanism. The postreceptor mechanism appears to be mediated by a c t i v a t i o n of protein kinase C which down regulates CCK receptors.

ELECTRICALLY INDUCED CHOLINERGIC AND NOR-ADRENERGIC, NONCHDLINERGIC DISTAL COLONIC CONTRACTIONS IN THE RAT, IN VIVO B. Gustafsson~ S. Nordgren, S. Fasth, L. Hult~n ( I ) and D. Delbro (2). Depts.of Surgery I I (11 and Physiology (2), of Ggteborg, SWEDEN. We have analysed the m o t i l i t y pattern ~nduced by electr i c a l stimulations of the d i s t a l colon. Male Sprague-Dawley r a t s , a f t e r induction with hexobarbitone i . p . , were a r t i f i c i a l l y v e n t i l a t e d . A carotid a r t e r y was cannulated f o r blood pressure recordings and f o r the administration of drugs. The rats were then e i t h e r pithed dr given supplement a r y anaesthesia (chloralose). A balloon was ihserted via the anus into the d i s t a l colon ( i . e . a segment of a length of 2 cm orad to the colonic e n t r y of the i n f e r i o r mesenteric a r t e r y . The ballon was f i l l e d with water and connected to a transducer f o r volume recordings, on a Grass polygraph. Field stimulation of the d i s t a l colon was performed by a b!polar electrode arranged around t h e gut, Stimulations ( I 16 Hz, I-5 ms, supramaximal i n t e n s i t i e s ) produced frequency ~ependent contractions (h=14) which were reduced by 20-30% by hexamethonium (25 mg/kg), suggesting that they were mai~ l y due to an a c t i v a t i o n of postganglionic neurones (n=2). Atropine (Img/kg), when given as the f i r s t drug (n=11) reduced the contractions by up to 80%. A f t e r atropine 'rebound contractions' were always observed, which were oresent also a f t e r the! addition of t e t r o d o t o x i n (20 ~g/kg) (n=1), suggesting a myogenic o r i g i n of these e f f e c t s . A f t e r a combination of guanethidine (8mg/kg), atropine and hexamethonium (doses as above) stimulations at high i n t e n s i t i e s s t i l l caused contractions which were abolished by naloxone (Img/ kg) (n=2). To conclude: Field stimulations o f the d i s t a l colon in the r a t , in v i v a , e l i c i t e d contractions which were due to an a c t i v a t i o n of mainly chOlinergic postganglionic f i b r e s . Also non-adrenergic, non-cholinergic naloxone-sens i t i v e contractions could be produced, which probably were caused by a s t i m u l a t i o n o f enkephalinergic postganglionic neurones. Supported by HFR (00016, 03117). Guanethidine was generously supplied by Ciba-Geigy AD.

RESPONSE OF HUMAN ESOPHAGEAL CIRCULAR SMOOTH MUSCLE TO TRANSMURAL STIMULATION IN VITRO. g.F. HeJm~ W.J. Dodds~ s.K. Sarna~ W.3. Hogan~ M.B. Adams~ a n d R.D. Layman. Medical College of Wisconsin, Milwaukee, WI~ U.S.A. In vitro studies of the human esophagus have been limited due to difficulty in obtaining specimens for study. We obtained viable human esophageal specimens for in vitro study from organ donors who had been declared legally brain dead. Seven transverse muscle strips were cut from the esophagus at 2 - c o intervals~ from 1 cm to 13 cm above the gastroesophageal junction. Each strip was suspended in its own muscle bath from a force transducer and stimulated transmuraily with 10-s trains of current pulses (160-320 ma, 0.5-2 ms duration, 2-40 hz). Resuits: Transmural stimulation evoked a contraction that occurred 0.5 s after stimulus onset (on contraction). On contractions were followed by a variable degree os relaxation of resting muscle tension during the remainder of the stimulus. A second contraction occurred a f t e r stimulus termination (off contraction). In strips from the most distal esophageal site, the dominant response was relaxation for the duration of the stimulus. On contractions were diminutive and seen only at 10-t~0 hz, while off contractions were of g r e a t e r amplitude and most consistently seen at freciuencies of 2-10 hz. Along the esophagus, we did not find a gradient in the latency of on contractions or off contractions a f t e r stimulus onset or offset, respectively. Atropine 10-6-I0-~M did not antagonize the response to stimulation. Tetrodotoxin t0-6-10-5M abolished the off Contraction and preceding relaxation, but prolonged the on contraction for the duration of the stimulus. We conclude: l)Transmural stimulation of human esophageal circular muscle elicits an intrastimuius on contraction and a post-stimulus off contraction with interposed relaxation. 2) The off contraction and preceding inhibition are mediated by noncholinergic nerves. 3) The on contraction may be mediated by tetrodotoxin-resistant noncholinergic nerves~ or may be due to direct muscle stimulation. 4) The absence of a gradient in the latency of either noncholinergJc on contractions or off contractions suggests that peristalsis in the human esophagus is not explained as a series of aborallydirected postganglionic on or off contractions. Extrinsic and intramural nerves, however, may serve to initiate and modulate contraction propagation that might be myogenic in origin.

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY STRUCTURAL DIFFERENCES BETWEEN GASTRIC AND AORTIC MYOSINS. D.J. HelDer and D,R, Hathawav. Indiana University School of Medicine, Indianapolis, IN 46202, USA Smooth muscle exists as two types in the GI tract, tonic and phasic. They can be distinguished by shortening veleeity (Vo), phasic having a s VO than tonic smooth muscle. Anatomically, tonic smooth muscle is localized to sphincters while the bulk of the GI tract contains phasic smooth muscle. The molecular basis for physiologic differences between phasic and tonic smooth muscle is unknown. We have discovered a structural difference between phasic and tonic smooth muscle myosins using purified aortic myosin (AMyo) as a model of tonic smooth muscle and gastric myosin (GMyo) as a model of phasic smooth muscle. Although both myosins contain 2 heavy chains (M~=200 kDa) and 2 sets of light chains (Mr=20 kDa and I~ kDa) that are indistinguishable by SOS-PAGE, isoeleetrlc focusing (IEF) reveals 2 variants of the 17 kDa light chain (LC17). These iEFvariants ape distributed differently in porcine aortic (40% LC17a, 60% LC17 b) and porcine gastric (100% LC17 b) smooth muscle. Amino acid analysis and reverse phase HPLC of tryptic peptides of purified LC17a and LCITb demonstrated significant differences consistent with differences in amino acid sequence. To determine whether GMyo and AMyo are f~nctionally different, aotin- activated MgATPase activities were measured in vitro. AMyn had a Vmax of .~ umol Pi liberated/min/mg with a Kap p for actin of 12 uM. For GMyo, the Vmux was .12 umol Pi liberated/min/mg and' the Kap O for actin, 10 uM. Our results suggest the following: ~) GMyo and AMyo differ structurally with respect to LCI7 isoform content, 2) MgATPase adtivities of GMyoand AMyo also differ, withVma x for GMyo being twice that Of AMyo, 3) the difference in MgATPase activities of GMyo and AMyo parallelsreported Vo measuremebtsof phasic and tonic smooth muscles, in conciueion, differences in the mechanical prOperties of smooth muscle subserving different functions in the GI tracs may be determined by expression of uniq6e isoforms of myosin.

DEVELOPMENTAL DIFFERENCES IN CALCIUM SOURCES UTILIZED FOR CONTRACTION IN THE CAT'S UPPER GASTROINTESTINAL TRACT. C. Hillemeier~ DominiqueBereiter, and Pe#er Biancani. Brown University and Rhode Island Hospital~ Providence, RI, 02902, U.S.A. Isolated c i r c u l a r smooth muscle cells from the esophagus, fundus, and antrum in the adult cat and newborn k i t t e n were compared. DOse response curves were obtained to Acetylchol i n e (Ach) in the presence of normal Calcium (Ca+2), zero Ca+2, and the Ca+2 channel blocker D600. Cells from the esophagus o f the adult and k i t t e n contracted s i m i l a r l y in Ca+2, but both f a i l e d to show any contraction in zero Ca+2 or D600. Fundic cells in both the adult and k i t t e n con: tracted the same in Ca+2, and also showed maximal contraction in Zero Ca+2 or D600. The c o n t r a c t i l e response of antral cells was no d i f f e r e n t between adult and k i t t e n in normal Ca+2. However, the adult antrum contracted 53.3% and 47.6% of maximum in zero Ca+2 and D600 respectively, while the k i t t e n ' s antrum contracted s i g n i f i c a n t l y less (p<.O01) at 6.4% and 3.2% of maximum. AntrM cells were then saponified (permeabilized) and exposed to i n o s i t o l t r i phosphate (IP3), which releases i n t r a c e l ! u l a r Ca+2 stores. A f t e r saponification and incubation in Ca+2-free (cytosoli medium, the adult antral cells contracted 52.1% in response to IP3, while the k i t t e n antral cells f a i l e d to contract. We conclude t h a t in respohse to Ach the esophagus and fundus of the adult cat and k i t t e n u t i l i z e similar Ca+2 sources, with the esophagus using e x t r a c e l l u l a r Ca+2 and the fundus depending upon i n t r a c e l l u l a r Ca+2 stores. ?he adult antrum is able to u t i l i z e i n t r a c e l l u l a r Ca+2 stores f o r part of i t ' s contraction while the k i t t e n is not. We speculate th~s may be due to a lack of i n t r a c e l l u l a r Ca+2 stores in the newborn k i t t e n antrum.

AGANGLIoNIC RAT JEJUNUM: A CHEMICALLY-INDUCEDEXPERIMENTAL MODEL. J.R. Herman, M.L. Epstein, and P. Bass. U n i v e r s i t y of Wisco~-sTn, Madison, WI., U.S.A. Serosal application of benzalkonium chloride (BAC) has previously been shown to ablate the myenteric plexus of r a t jejunum with l i t t l e e f f e c t on the submucosal plexus (JPET, 1983, 227:538). We have found that serosal application of a Combination of BAC and calcium chloride ablates both myehteric and submucosal neurons of raB ~e~unum. The optimal combination f o r t o t a l enteric nervous system ablation was found to be 0.031% BAC and 1,3% calcium chloride applied f o r 30 minutes. Cryostat sections from control and treated tissues Were stained with antisera to neuronspecific enolase (NSE), neurofilament proteins (NF) and vas~active i n t e s t i n a l peptide (VIP) 15 days posttreatment. Fluorescent microscopic examination indicated no NSE, ~!F, or VIP immunoreactivity in the myent~ric region and greater than 90% reduction of these markers in the submucosal region Of treated tissue Yelative to control tissue. Light microscopic examination of p l a s t i c embedded, methylene blue basic fuchsin-stained tissues indicated a s i g n i f i c a n t loss of neurons in both plexuses. The few cells which remained in the submucosal region exhibited signs of degenerative chahges, including c e l l u l a r and nuclear swelling, chromatin clumping, and apparent less of cell membrane. In a d d i t i o n , many of the remdining Cells exhibited p o s i t i v e staining to g l i a l acidic f i b r i l l a r y protein antisera, suggesting that these cells may be reactive g l i a l c e l l s . Smooth muscle layers were moderately thickehed, but otherwise appeared normal. The mechanism by which the BAC-calcium combination can ablate both myenteric and submucosal plexuses (vs. myenteric ablation with BAC alone) may involve calciuminduced stasis of submucosal blood flow. This stasis may permit greater exposure of subNucosal neurons to the lethal e f f e c t s of BAC. This model permits the study of i n t e s t i n a l function in the absence of enteric neurons. (Supported by ~!IH grants DK3259~ (PB) and DK32978 (MLE))

SOURCES oF Ca++ FOR CONTRACTION OF SMOOTH MUSCLE CELLS FROM ESOPHAGUS, LOWER ESOPHAGEAL SPHINCTER (LES) AND GASTRIC FUNDUS OF CAT. C. Hillemeier, P. Biancani, J.R. Grider, K.N. B i t a r . Rhode ~ a 6 d H o s p i t a l and Brown U n i v e r s i t y , Providence, RI, 02902; Medical College of V i r g i n i a , Richmond~ VA, 23298, U,S.A. Muscle cells were isolated from the c i r c u l a r layer of esophageal, LES, and the gastric fundus and used as suspension to examine the role of i n t r a c e l l u l a r and e x t r a c e l l u l a r Ca++ in mediating contraction induced by acetylcholine (Ach), cholecystokinin (CCKI , i n o s i t o l trisphosphate (IP3) and the protein kinase C (PKC) a c t i v a t o r phorbol 12myristate 13-acetate (PMA). Contraction induced by Ach and CCK Was mediated by Ca++ i n f l u x in esophageal ceils and by Ca++ release from i n t r a t e l l u l a r stores in LES and fundus cells. The evidence f o r this is as follows: i . Incubation in Ca++-free medium (0 Ca++ + lmM EGTA) blocks contraction in esophageal cells but not of fundus or LES cells. 2: Substituting Ca++ with Sr ++ blocks contraction of LES and fundus cells but not of esophageal c e l l s . 3. Cytosolic Ca++ , measured with the fluorescent i n d i c a t o r quin2, i n creases in esophageal and LES c e l l s in response to CCK in normal (2mM) Ca++ medium, but only in LES cells in the presence of the Ca++ channel blocker methoxyverapamil. 4. After permeabilization with saponin and incubation in Ca++free " c y t o s o l i c " medium, LES and fundus but not esophageal cells contracted in response to IP3. The PKC a c t i v a t o r PMA Contracted esophageal, LES and fundus muscle in normal (2mM Ca++) medium. I t contracted LES and fundus but not esophageal cells in Ca++-free medium and contracted esophageal but not LES or fundus cells when Sr ++ was substituted f o r Ca++i In conclusion: agonist-induced contraction is mediated by Ca++ i n f l u x in esophageal muscle cells and by Ca++ release in LES and fundus c e l l s . In permeabilized c e l l s , IP3 induces contraction only in cells (LES and fundus) t h a t are sustained by i n t r a c e l l u l a r Ca++ release. F i n a l l y , contraction mediated by phorbol esters depend on Ca++ release in LES and fundu~ c e l l s , and on Ca++ i n f l u x in esophageal muscle c e l l s .

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Digestive Diseases and Sciences, Vol. 32, No. 8 (August 1987)

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY ANTROPYLORODUODENAL MOTOR RESPONSES TO INTNADUODENAL ACID INFUSION IN H E A L T H Y VOLUNTEERS. L.A. H o u g h t o n , D.D. Kerrigan, N.W. Read, and A.G. Johnson Department of Surgery and S u b - D e p a r t m e n t of H u m a n G a s t r o i n t e s t i n a l Physiology and Nutrition, University of Sheffield, UK. I n t r a d u o d e n a l acid has been s h o w n to s l o w g a s t r i c emptying. In o r d e r to i n v e s t i g a t e the m e c h a n i s m s responsible for this effect we recorded pressure activity in the antrum (3 sites), pylorus and duodenum (4 sites) in 7 healthy volunteers under fasting conditions and during intraduodenal infusion of normal saline and isotonic 0.1M hydrochloric acid, given alternatively for consecutive 30 m i n u t e p e r i o d s for up to 2.5hrs. P y l o r i c p r e s s u r e was recorded u s i n g a 4.Ocm long sleeve s e n s o r p o s i t i o n e d by m e a s u r i n g the t r a n s m u e o s a l P.D. at e i t h e r end of the sleeve. I n t r a l u m i n a l pH was m e a s u r e d in the t e r m i n a l a n t r u m and at two p o s i t i o n s in the proximal duodenum, S a l i n e and acid w e r e infused into the d u o d e n a l bulb at a rate of e i t h e r I m l . m i a -I or 2 m l . m i n -I d e p e n d i n g on the a m o u n t of acid r e q u i r e d to reduce i n t r a d u o d e n a l pH to between I and 2. The most common motor pattern recorded under fasting conditions and d u r i n g i n t r a d u o d e n a l s a l i n e i n f u s i o n c o n s i s t e d of r e g u l a r co-ordinated contractions i n v o l v i n g the d u o d e n u m and e i t h e r the a n t r u m a n d / o r the pylorus. M o s t of these c o - o r d i n a t e d e v e n t s s h o w e d e v i d e n c e of p r o p a g a t i o n t h r o u g h two or m o r e a d j a c e n t channels and were associated with transient reductions in d u o d e n a l pH. W i t h i n 5 mine of the start of the acid infusion there was (I) a s~gnificant reduction of antral p r e s s u r e w a v e s [acid, 2hr?4 (O-54hr'I), m e d i a n (range); saline, 90hr -I ( 2 6 - 2 7 2 h r - ) : p
OSMOCALORIC REGULATION OF GASTRIC EMPTYING (GE) AFTER DUODENOJEJUNOSTOMY (DJ). K.M.F. Itani, R.E. Coleman, O.E, Akwari. Duke University, Dept. of Surgery, Durham, NC 27710. Gastric emptying is thought to be regulated by duodenal mechanisms sensitive to the osmolarity and caloric content of ingesta. The extent to which such control occurs in the jejunum remains unclear. Method: Sixteen dogs with intact gastrointestinal tracts underwent testing of GE using so• t• techniques. In eight of the dogs the duodenum was transected 2cm distal to the pylorus with end-to-side DJ 20 cm distal to the ligament of Treitz, On different days, one month after operation, the fasted dogs had GE measurements during empytin 8 of 170ml of normal saline (AI), 340mi of normal saline (Ap), 170 ml of 20% glucose (BI), 340mi of 20% glucose (B2), 170ml of a saline solution • with 20% glucose (C) and 170mi of 50% glucose (D). Results: During duodenal delivery, GE was significantly retarded by increasing osmolarity ( A i v s C; Bp vs D), but increasing volume (A; vs Ag; B] vs np) and c~loric content ( B ] v s B 2 vs D) had no~signi~ica~t effects. The pattern of sloQiag o~ GE resulting from increasing the osmolarity of the instillate ( A ] v s C; B~ vs D) was preserved after DJ. Increasing the voIume of t~e caloric meal (B vs B ) but not the nonealoric 2 meal (A I vs A 2) slowed GE. T~is slowing resulted from differences in caloric content ( B ] v s B2 vs D) rather than volume. Conclusion: We conclude ~hat sIowing of GE of caloric meals during their duodenal delivery is primarily mediated through mechanisms which are sensitive to osmolarity, In the jejunum this effect of osmolarity is potentiated by the caloric content of the meal but not its volume. These mechanisms must be considered in the assessment of functional results of operations resulting in direct jejunal delivery of ingesta. GASTRIC HALF-EMPTYING TIME (MIN) MEALS INTO 27.88 A~ B~ ]B~ C D Duod . . . . 25.0 84.~ 111 63.5 163.2 • • • • • • Jejunum 27.9 25.9 80.3 157.8 55.2 199.6 • • • • • * • Mean • N=8; *Differs from B 1 (jejunal delivery) p<0.05 by paired t-test

REVERSIBLE UNCOUPLING OF COLONIC SMOOTH MUSCLE CELLS FROM THEIR PACEMAKERS. J.D. Muizinga and E. Chow. Intestinal Disease Research Unit, MeMaster University, Hamilton~ Ontario. Canada LSN 3Z5 Electrical coupling between "submucosal" circular muscle cells of the dog colon was investigated by measuring the tissue length constant (~) in an Abe Tomita stimulating chamber, and by measuring s l o w wave synchronization. Cells at the submucosal side showed omnipresent slow wave activity (28 mV; 6 epm). Eleatrotonic potentials showed exponential decay giving a of 2.6• nun, and a time constant (r) of 157• ms (n=15). Heptanol, 0.2 mM, depolarized the cells by II mY, decreased slow wave amplitude, but did not alter membrane resistance (measured from I/V relationship and ~) nor A. With heptanol, 0,5 ~ , slow wave activity disappeared and no electrotonic potentials were recorded as close as 1 mm from site of current injection; A decreased to < 0.2 mm. After washout of heptanol, eleetrotonic current spread and slow wave activity recovered, Synchronization of slow wave activity, measured by simultaneous recording with 7 extracellular electrodes, markedly decreased in the presence of 0.35 mM heptamol, and slow wave activity was recorded from more than one pacemaker area at most recording sites. D600 (IO'6M) was introduced to render cells •177 the cells depolarized 18 mV and slow wave activity disappeared (a situation similar to heptanol 0.5 mM), however I increased to 7.1• mm, probably due to the observed increase in membrane resistance. 50% sucrose (92 g/i)-50% Krebs was introduced to study the effect of increase in resistivity of the extraoellular fluid and increased membrane resistance on l, which increased to 5.8• mm. The data are consistent with the hypothesis that heptanol reversibly inhibits intercellular coupling, resulting in loss of spread of extracellularly injected current and uncoupling of cells from the pacemaker cells. The data are not consistent with the model Sperelakis (Innov.tech.biol.med. 7(1986)433) proposes, which suggests that extracellularly applied current in the Abe Tomita bath is carried through the extracellular space,

MOTiL!DE, A NEW FAMILY OF MACROLIDE COMPOUNDS MIMIOING MOTILIN. Z. Itch and g. Omura. Gastroenterology Lab, College of Medical Technology, Ounma University. Maebashi~ and The gitasatc institute~ Tokyo~ Japan. Recent our finding that erythromycin (EM)~ one of the la-membered macrolide antibiotics mimics motllin prompted us to study the relationship between the chemical structure of macrolide compounds and activity to induce the interdigestive migrating contractions among more than 200 derivatives newly synthesized for this s t u d y , gastrointestinal (Gi) motor stimulating activity was assayed in dogs with transducers implanted and in the isolated rabbit duodenum. Among derivatives subjected to the first stage of modification of EM~ 8,9 anhydroerythromycin A 6~9-hemiketal (EM 201), in which an oxygen bridge was constructed between C6 and C9 within the laetone ring structure, increased the activty to IO. EM 201 was modified further and it was found that the dimethylamino group of desosamine is a very important site for Gl motor stimulating activity; for instance~ the addition of methyl or ethyl radicals to the dimethylamino group to yield quarternary amine increased the activity to about i00, and the addition of allyl (EM 511) and propagyl (EM 536) radicals increased it to 253 and 2890~ respectively. Most of the derivatives wlth potent Gl motor stimulating activity lost antibacterial activity. In in vitro studies~ EM 536~ the most potent derivative, stimulated isolated ~uodenal segments with the minimum effective dose at IO-~M and the EC value was 5.3 nM~ ' 50 this was comparable to that of motilin (1.2 aM). Dose-response studies reve~!ed that a parallelism was clearly established between the dose response curves for EM derivatives and motilin. Contractions induced by EM derivatives were not influenced by pretreatment of the isolated duodenum with atropine, hexamethonium~ or tetrodotoxin but were strongly suppressed by the removal of Ca ions from the media or by the addition of varapamil. In vivo and in vitro activity of the EM derivatives was identical to that of motilin. In conclusion~ there is a new family of macrolide compounds which mimic peptide hormone motilin and we propose to name this new family of macrolide compounds "motilide". (A-16)

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY NANC NERVE MEDIATED CONTROL OF THE CIRCULAR MUSCLE OF THE OPOSSUM ESOPHAGUS. L.P. Jager*, J. Jury, V. Posey-Daniel, E.E. Daniel *Dept. Pharmacology, Central Veterinary Institute, Lelystad, the Netherlands, and Dept. Neurosciences, McMaster University, Hamilton, Canada. The structural and functional characteristics of the intramural innervation of the esophageal circular muscle were studied using histological and electrophysiologieal techniques. The muscle is densely innervated by nerves with varicosities containing many small agranular vesicles and a few large granular visicles. Only one type of nerve mediated responses could be observed: an inhibitory junction potential (IJP), of which the hyperpolarization is followed by a relatively long lasting depolarization, usually crested with muscle action potentials, governing a transient contraction. The IJP was neither mimicked nor blocked by specific agonists or antagonists of adrenergic, cholinergic, purinergic or peptidergic neurotransmission. The peptidergic assumption was tested with VIP, because VIP-like immunoreactive material was found in many nerves of esophageal circular muscle. Although the IJP is mediated via a selective increase in the membrane permeability towards K-ions, the response could not be blocked by K-channel blockers. Nerve varicosities were more closely related to interstitial cells of Cajal (It) than to smooth muscle cells.and the presence of gap junctions between smooth muscle cells, between IC and between smooth muscle cells and It. This was paralleled by the electrophysiological observations of a two peaked frequency distribution of IJP latencies. The short latencies seem to be due to impalements of IC whereas the longer lateneies are attributed to IJP recorded from smooth muscle cells. The conclusion is reached that in opossum esophagus peristaltic propulsion is mediated via intramural NANC-nerves, which can initiate both the receptive relaxtion and the propulsive contraction of the circular muscle layer. Circumferential coordination of the motility of the esophageal wall is achieved by release of a unknown neurotransmitter, to loosely defined motorunits in which, via gap junction contacts, transmitter effects spread from interstitital cells to smooth muscle cells.

THE DYNAMICS OF THE SWALLOW REFLEX WITH AND WITHOUT TOPICAL OROPHARYNGEAL ANESTHESIA PJ Kahrilas. JA Loeeman. NB Vakil. WJ Dodds. J Dent. SL Tarbis. Dept of Med & ENT Iqorthwestem University and VALMC, Chicago, I1. USA The relative timing of the motor events comprising the swallow reflex are subject to feedback regulation that is influenced by the volume of the bolus swallowed (1) We sought to determine whether or not this feedback regulation was dependent upon oral tactile sensation. 9 healthy volunteers were studied without anesthesia (NA) and following Cetacalne anesthesia to the posterior oral cavity (A) such that a gag reflex could not be elicited with a cotton swab. Subjects were intubated transnasally with a UES sleeve assembly (sleeve sensor posterior, side-hole sites at 0,2,&4 cm from the superior margin of the sleeve on the anterior face) and had EMG electrodes positioned over the mylohyoid (MH) and thyrohyoid (TH) muscles. Three 0,2,5,10, and 20 ml water swallows were recorded without and with oral anesthesia. UES relaxation (R), pharyngeal contraction (PC) and UES contraction (C) were scored from the manometric recording by means of a radiographically validated method (1), The onset of MH and TH EMG activity were scored blindly. Results All of the intervals measured were strongly correlated with swallow volume. MH-R is indicative of the delay in initiation of the swallow reflex. None of the reflex. , the anesthetic (Table). Water R-PCt" R-Ct" MH-R? TH-RI" Volume NA A NA A NA A NA A Oral 23+4 23+_2 40!-_3 36+2 70!-_9 69+9 22+2 24+3 2 ml 29+4 26+3 43+3 40-+3 72+9 65+8 19+3 21+_2 5 ml 34+4 33+3 50-+3 53+_5 66+9 56+9 15+3 15+_2 10ml 37+3 37+2 56_+3 51_+3 52+8 53+7 13+3 13+2 20ml 43+3 38+3 62+4 55+3 46+7 52+8 10+3 12+2 correr~" 0.99* 0.98* 0.984 0.96* 0.99* 0.93 ~ 0.99* 0.947 "Interval (Mea~+SEM) in hundredths of.a sec t"~Polynomial correlatiot coefficient between column parameter and swallow volume. *p<0.01 Conclusions: 1).Oral topical anesthesia does not compromise either a) the ability to voluntarily initiate a swallow or b) the sensory feedback occurring during the swallow that modifies the temporal profile of the swallow reflex according to bolus volume. This suggests that the necessary sensory feedback arises from proprioceptors. 2). The absence of a gag reflex does not affect the ability to swallow normally. 1. Kahrilas PJ, et al. The dynamics of pharyngeal and upper esophageal sphincter function during deglutition.Gastroenterology,InPress(abstract).

ELECTROPHARMACOLOGICAL CHARACTERISATION OF NANC NERVE MEDIATED INHIBITION IN PORCINE COLON.

THE EFFECT OF INTRACEREBROVENTRICULARPERFUSION WITH CCK-OP ON GASTROINTESTINALMYOELECTRIC ACTIVITY IN THE DOG. R. Karmeli, C. Kamei, P. Schmalz T. Yaksh and J.H. Szurszewski, Mayo Medical School, Rochester, MN 55905 USA. The effect of continuous perfusion of the lateral and fourth ventricles with CCK-OP on the myoelectric a c t i v i t y of the stomach and the small intestine was examined in four conscious dogs. Electrical a c t i v i t y was monitored by electrodes implanted along the stomach and small intestine. Following a ten day recovery period, fasting and fed myoelectric activities were recorded daily for one week. Thereafter, a second surgical procedure was performed on the same dogs to chronically position catheters in the lateral and fourth cerebral ventricles. Following recovery, experiments were conducted to determine the effects of continuous perfusion of the lateral to the fourth intracerebral ventricles with a r t i f i c i a l CSF and CCK-OP-containing CSF. Continuous perfusion with a r t i f i c i a l CSF had no effect on the MMC pattern. However, continuous perfusion w~h a r t i f i c i a l CSF containing CCK-OP at a rate of 1.5 x 10- ~ M/min abolished endogenously occurring MMCs in 3.3 f 0.5 minutes (mean • SE, N:IO) and a fed-like pattern appeared. The fed-like pattern f i r s t occurred in the stomach and duodenum, then progressed d i s t a l l y to the ileum. The fed-like pattern continued at all sites during the entire period (110 min, N=11) of CCK-OP perfusion. When ventricular perfusion with CCK-OP was stopped, an MMCpattern returned in 4.7 • 1.1 minutes (mean • SE, N=9). Of those that returned, 72.8% started in the duodenum and 27.2% in the jejunum. Ventricular perfusion with non-sulfated CCK and i . v . infusion with sulfated and nonsulfated CCK, at the same rate and concentration used for perfusion of the cerebral ventricles had no effect on endogenously occurring MMCs. These data suggest that endogenous sulfated CCK-OP released in the brain may play a role in converting the fasting pattern of myoelectrical a c t i v i t y to a fed pattern in the dog. (Supported by NIH DK 17632 and the Rappaport Scientific Exchange and Research Program.)

L.P. JaKer, M.W.G. van der Schaar, Dept. Pharmacology, Central Veterinary Institute, Lelystad, the Netherlands. Field stimulation of strips from the circular smooth muscle layer of porcine colon induced NANC nerve mediated inhibitory junction potentials (IJP). The increase in membrane conductance during the IJP and a reversal potential more negative than the resting membrane potential suggested that the IJP is generated via K-channels. These and other physiological characteristics are similar to those of the NANC nerve mediated IJP in guinea pig taenia caeci (LM), (Methods in Pharmacology 6, 1985: 359-379) and in opossum esophageal circular muscle (CM), (J. Physiol. 1983, 336: 243-260; Can. d. Physiol. Pharmacol. 1985, 63: I07-I02). The pharmacological characteristics of the porcine IJP determined sofar accentuate two differences between the NANC inhibition in the three preparations. I. Apamin~ which blocks Ca-dependent K-channels, does block the porcine IJP in contrast to CM, but as in LM. II. Neither agonists or antagonist s of purinergic or peptidergic (VIP) nerves mimicked or inhibited the porcine IJP, in contrast to LM, but as in CM. The present findings suggest that NANC nerve inhibition in mammalian gi-tract is brought about via similar K-channels, which can be operated via different receptors. This might imply that inhibitory NANC nerves release different transmitters in different mammalian species.

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Digestive Diseases and Sciences, Vol. 32, No. 8(August 198~

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY IONIC SPECIFICITY OF CALCIUM CHANNELS IN THE VISCERAL MY0CYTE. D, Katzka, N. Morad. University of Pennsylvania School of NedJcine, Philadelphia, PA. 19104-4283, U,S,A. Ionic channels from excitable cells may conduct more than one ion, species and cell t~0e. Aim: To determinethe ionic specificities of the calcium and calcium activated and voltage dependent potassium channels in guinea pig gastric myocytes. Methods: Guinea pig corpus cells were isolated by enzymatic perfusion of the stomach wall. Voltage clamp and internal dialysis of individual cells were done by whole cell variation of the patch clamp technique (Hamill et el, 1981). A clamp frequency/duration os 0,2 Hz/70 msec and holding potential of -60 to -90 mV were used for all experiments. Results: With a 140 r~ K+ internal solution and a S.0 mM Ca2+ Tyrode's external solution, depolarization os gastric myocytes produced transient inward Ca2+ current (liCa2+) followed by outward K§ current (IoK+) which persisted for the duration of the 70 msec pulse. IiCa2+ was activated at -40 mV, peaked in amplitude at 0 mV and reached apparent reversal at +40 mV. IoK+ was similarly activated at -40 mV but its amplitude increased with increasing depolarizations up to +I00 mV tested. When S mM Sr2+-Tyrode's was substituted for Ca2+ there was a complete loss of inward current (Ii) and a net increase in IoK+ at depolarization positive to -40 mV. In some experiments, IoK+ was markedly increased compared to that seen with Ca2+. When S mM Ba2+ replaced Ca2+ an initial decrease in IoK+ was seen followed by a net increase in Ii. A recorded increase in membrane conductance suggested a greater increase in Be2+ conductance through the calcium channel than Ba2+ inactivation of the Ca2+ activated K+ channel. Both activation and inactivation kinetics of li decreased, At potentials positive to +40 mV, IoK+ was increased with Ba2+ when compared to Ca2+. Perfusion with I00 ~m Cd2+ Tyrode's eliminated li completely. Conclusions: In guinea pig gastric myocytes, i. The calcitml channel is highly permeable to Ba2+ but not St2+ or Cd2+, 2. The Ca2+ activated K+ channel is specific for Ca2+, 3. Ba2+ and St2+ do not inhibit the voltage dependent K+ channel, and may activate it, 4. Mammalian visceral myocyte channels show different ionic specificities than those described for cardiac or neuronal cells.

GASTRIC DYSRHYTHMIASAND NAUSEA OF PREGNANCY. K.L.Koch, G.W. Creasy, A,Dwyer, M.Vasey and R.M.Stern. Departments of Medicine, Obstetrics and Gynecology, and Psychology. The Pennsylvania State University, Hershey and U n i v e r s i t y Park, PA 17033 USA. Gastric dysrhythmias may play a role in a v a r i e t y of nausea syndromes. Nausea occurring in the f i r s t 16 weeks of pregnancy is a common symptom, but the pathophysiology of nausea of pregnancy is unknown. The aim o f this study was to determine gastric myoelectric a c t i v i t y in pregnant women with symptoms o f nausea. T h i r t y - t h r e e women (ages 19 to 32 years) with nausea ascribed to pregnancy were studied. Mean gestation was 10,9 weeks. Gastric myoelectric a c t i v i t y was measured with cutaneous electrodes which yielded e l e c t r o gastrograms (EGGs), EGGs were recorded f o r 30-45 minutes on chart paper and magnetic tape, the l a t t e r f o r subsequent spectral analysis o f the EGG signal, On the day of study, patients fasted approximately 2.5 hours before EGGs were obtained, completed a s~ptom questionnaire and indicated t h e i r current i n t e n s i t y of nausea on a 300 mm visual analog scale. Sixteen age-matched women served as controls and EGGs were recorded as described above, The predominant EGG frequency was determined v i s u a l l y and by results of the running spectral analysis. Results: Gastric dysrhythmias were found in 26 of 32 women: 15 had tachygastrias (EGG frequencies from 4-9 cpm); and 11 had bradygastrias; 5 had a i cpm large amplitude pattern; and 6 had a f l a t l i n e pattern. Six patients had normal 3 cpm rhythms. The mean nausea scores (O=no nausea and 300 mm=severe nausea) of the patients were: 2.9 f o r the 3 cpm group;,~64.8 f o r the tachygastrias; 93.4 f o r the 1 epm pattern; and 77.2 f o r the f ~ a t l i n e pattern. Mean nausea score i~ the 3 cpm group was s i g n i f i c a n t l y d i f f e r e n t from nausea scores in the dysrhythmia groups. Control subjects reported no symptoms on the day of study and 15 of 16 had the 3 cpm EGG pattern; one control had a f l a t l i n e pattern. In conclusion: l ) G a s t r i c dysrhythmias are common in women with nausea of pregnancy; 2 ) I n t e n s i t y of nausea was s i g n i f i c a n t l y greater in women with gastric dysrhythmias compared to those with 3 cpm patterns; 3) Gastric dysrhythmias may contribute to the pathogenesis of nausea of pregnancy.

CHARACTERIZATION OFSEROTONiN (5-HT) RECEPTOR SUBTYPES ON iSOLATED HUMAN JEJUNAL SMOOTHMUSCLE CELLS. J.M. Kellum and J,R. Grider. Medical College of V i r g i n i a , Richmond, VA. Three subtypes of serotonin receptors have now been i d e n t i f i e d based on the a b i l i t y of s e l e c t i v e antagonists to block the response to serotonin. Ketanserin is selective f o r the 5-HT2 receptor and ICS 205-930 f o r the 5-HT~ receptor. A s e l e c t i v e antagonist is not available ~or the 5-HT1 receptor, which is i d e n t i f i e d by resistance to antagonism by ketanserin and ICS 205-930. The p r e s e n t study was designed to characterize 5-HT receptors on human i n t e s t i n a l smooth muscle c e l l s . Muscle c e l l s were isolated separately from the longitudinal and c i r c u l a r muscle layers of human jejunal segments obtained at bypass surgery f o r morbid obesity. The muscle c e l l s were examined f o r t h e i r response to 5-.HT (0.] pM - 10 uM) alone and in the presence of 0.1 uM methysergide, ketanserin or ICS 205-930. C o n t r a c t i l e response was measured by scanning micrometry and expressed as percent decrease in cell length from control. 5-HT caused a concentration-dependent contraction of c e l l s from both longitudinal and c i r c u l a r muscle layer. The pattern of response was identical in the two cell types (maximal response at 0,I uM: 29.9• vs 30.3• DS~ 0.2 vs 0.3 riM). ICS 205-930 had no e f f e c t on 5-HTinduced contraction of longitudinal or c i r c u l a z muscle cells. Ketan!;erin and methysergide inhibited the response in both cell types, s h i f t i n g the concentration-response curves to the r i g h t . The K. values calculated from the l a t e r a l s h i f t s of the curve~ were 1.3 nM f o r ketanserin and 0 . i nM f o r methysergide. Antagonism by ketanserin implied the existence of a 5-HTp receptor mediating contraction. The lack of e f f e c t of ICS 205-930 implied the absence of a 5-HT~ receptor; this receptor appears to be confined to neur%l tissues. The existence of a 5-HT receptor could not be determined since methysergide, despite i t s potency, + does not distinguish 5-HTI from 5-HT2 receptors. In conclusion: human i n t e s t i n a l muscle c e l l s possess 5-HT, but not 5-HTq receptors. The existence of 5-HTI receptors and the Kature of the function (contraction or r e l a x a t i o n ) they mediate remains to be determined.

ROLE OF PEPTIDE YY (PYY) IN THE F1YOELECTRIC ACTIVITY OF THE SNALL BOMEL AND PANCREATIC

S,d, Konturek L

pmol/kg-h) in fasted dogs increased dose-dependently the MMC interval from control value of 83 • 7 to 369 • 8 min and inhibited
sodium oleate was perfused through the ileum dt the rate <2-16 mmoles/h) that increased plasma PTY to the levels s i m i l a r to those seen a f t e r infusion of exogenous PYY, Upon withdrawal of PYY infusion, the next phase I I I of HHC appeared in the duodenum w i t h i n about I5 min. In fed dogs, exogenous

PYY also exerted an inhibitory

e f f e c t on the i n t e s t i n a l spike a c t i v i t y and reduced dosedependently the postprandial pancreatic secretion. Ileal oleate failed to reduced the postprandial spike activity though it diminished s i g n i f i c a n t l y the pancreatic secretion. Pretreatment with alpha- and betaadrenergic blockers (phentolamine plus propranolol) abolished the effects of exogenous PYY and ileal oleate on fasted and f e d - l i k e m o t i l i t • pattern of the small intestine and reduced significantly the inhibitory e f f e c t s of PYY on pancreatic secretion. We conclude that exogenous. PYY and that released endogenously by ileal oleate inhibit intestinal motility and pancreatic secretion in fasted and fed dogs and that these effects are mediated, at least in part, by adrenergic pathway.

(A-18) Digestive Diseases and Sciences, Vol. 32, No 8 (August 1987)

SECRETION,

P. Thor, d . N . Konturek and J. La~kiewicz . Inst. Physiol. Krakow, Poland. PYY is an ileocolonic peptide which is released by i n t e s t i n a l perfusion Mith oleate and which i n h i b i t s pancreatic secretion. The aim of this study was to determine the e f f e c t s and the mode of action of PYY on i n t e s t i n a l m o t i l i t y pattern and pancreatic secretion in dogs equipped with monopolar sePOSat electrodes along the small i n t e s t i n e , the pancreatic f i s t u l a and the ileal fistula. PYY infused i , v , in graded doses (50-400

917

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY QUANTITATIVE MEASUREMENT OF FELINE COLONIC PROPULSIVE ACTIVITY. B. Krevsky, L.S. Malmud, A.H. Maurer, Y. Milewski, J. Siegel, and R.S. Fisher, Temple University School of Medicine, Philadelphia, PA 19140 U.S.A. Existing methods f o r evaluating colonic m o t i l i t y such as p e l l e t t r a n s i t , myoelectric recordings, intraluminal manometry and barium roentgenography cannot q u a n t i t a t i v e l y analyze the propulsion of colonic contents. To overcome this problem, dynamic colonic t r a n s i t scintigraphy was employed in 6 female adult cats to study propulsion q u a n t i t a t i v e l y in v i v o . I00 ~Ci of In-IlI-DTPA in a volume of 2 mi were i n s t i l l e d i n t o the cecum through a s u r g i c a l l y implanted s i l i c o n e cecostomy tube. Using l i g h t sedation, 300 sequential images of 10 sec duration were acquired over 50 min with a gamma camera interfaced to a d i g i t a l computer. For computer analysis, the colon was divided into 3 primary regions of i n t e r e s t : cecum and ascending colon (CAC), transverse colon (TC), and descending colon (0C). The e n t i r e CAC was subdivided into contiguous thin regions of i n t e r e s t , each 0.882 cm long. A rapid decrease in a c t i v i t y from the CAC region followed by sequential increases in both the TC and DC was defined as a mass movement. This event occurred an average of 1.0+0.0 (mean + SEM) times/50 min. The time from the s t a r t of The mass movement u n t i l a c t i v i t y increased in the DC was 3.3+0.92 min (range 0.5-8 min). Antegrade propagated ~aves over at least 2 segments (1.76 cm) of the CAC were observed in a l l animals, occurring an average of 2.33+0.49 times/50 min (range 1-4). The mean duration was 4.17+0.86 min (range 1.32-13.12), with a mean propagation length of 3.9+0.33 cm (range 1.76-6.17). The propagation velocity ~s 1.25+0.18 c m / m i n (range 0.336-2.149). On occasion, antegrade propagated waves in the d i s t a l CAC occured simultaneously with the i n i t i a t i o n of a mass movement. Conclusions: Dynamic colonic t r a n s i t scintigraphy is a new technique which can be used to describe the frequency, distance, and propagation v e l o c i t y of propulsive waves in the cat colon. Quantitative information a b o u t mass movements from the cecum to the descending colon can also be obtained. This technique may allow new insights into colonic propulsive physiology.

THE I~OLEOF THE ENTERICNERVO[B SYSTfiM IN THE INITIATIONAND PI~DPAC.~TION OF THE C.O~STI~DINTESTINAL MUrOR (3ORREIATES OF g]MITING. I.M. Lang, J. Marvigand S.K. Sarna. Medical COllege of Wisconsin and Zablocki VAMC,Milwaukee, WI 53295, LSA. The gastrointestinal (GI) motor correlates of vomiting include I) a retrograde giant contraction (NGC), 2) a periBGCper!ed of inhibition of other contractions, and 3) a postN[3C series of phasic contractions. The CNS triggers initiation of these motor events through the vagus nerves, but the role of the ENS is unknown. We determined the role of the ENS by comparing the effects of various neurotomies. Nine dogs were chronically imp}anted with i0 to 12 strain gage force transducers on the ston~ch and small intestine. After recording control responses to the 6metic, apomorphine (2.5 to Ig ~g/kg, i . v . ) , the dogs were subjected to I) myetomy of the proximal jejunum(MY), 2) transection and rean@stomosis of the proximal jejunum (TR), or 3) transection of the mesenteric nerves supplying 30 to 80cmof the proximal jejtmun (TN]N). We found that MYor TReliminated the gastrointestinal motor corre]ates of vomiting for 25 ~ 5 cmaboradof the cuts. Responses above the cuts were unaffected. However,the l ~ above the cuts began before the 8GC below the cuts ended. After TMN, the l ~ w a s blocked for i0 to 20 on below a 30 cm length of extrinsically denervated jejunum. The peri-l~3C inhibition but not the I~GCwas e]iminated in the extrinsically denervated segment. Responses above the extrinsically denervated intestine w e r e unaffected. T h e s e results suggested that the ENS participates in the control of both initiation and propagation of the GI motor correlates of vomiting. Themyenteric plexus mediates 1) activation of the GI motor correlates of vomiting through a descending pathway, and 2) inhibition of premature occurrence of the RGCthrough an ascending pathway. The suhmucosal plexus may not participate in the control of the GI motor correlates of vomiting. Themesenteric nerves mediate p e r i - l ~ inhibiton, and therefore, this inhibition may represent feedback inhibition of the propagating I ~ through intestinointestinal inhibitory reflexes. Supported in part by VA grant 5120-02P and NIH IX32346.

INTERACTION OF FOOD AND SLEEP IN THE MODULATION OF HUMAN PROXIMAL SMALL BOWEL MOTILITY. D Kumar, EE Seller, J Britto, A Das-Gupta, K Mridha, DL Wingete. GI Science Research Unit, London Hesp Ned Cell, London El 2A3, UK. In healthy ambulant subjects taking normal mid-day (MM) and evening (EM) meals, Phase II activity is virtually absent during sleep, and nocturnal MMCs are more frequent than diurnal MMCs (Gastroenterol 1987, abstr in press). We have tested the effect of the presence of food in the gut during sleep. Proximal small bowel motility was continuously measured in 8 healthy ambulant subjects via 2 strain gauge transducers attached to a fine (2.5 mm OD) nasojejunal tube. On the first day, subjects ate a standard 540 calorie meal (EM) between 1800-1900 hours, and went to sleep between 2500-24D0 hours. On the next day, they had a standard meal between 1300-1400 hours (MM) and then identical late mea] (LM) between 2300-2400 hours, 15 minutes before going to bed; all subjects were soundly asleep within 30 minutes of completing their meal. Motility was recorded on magnetic tape and subsequently analysed to determine the duration of postprandial activity, diurnal and nocturnal MMC period, and diurnal and nocturnal duration of Phase II activity. There was no difference in the duration of postprandial activity following MR (271+62 min) and EM (280+40 min), but postprandial activity was significan[ly (p
EFFECTS OF VIBRIO CROLERAE, WITH AND WITHOUT ENTEROTOXIN PRODUCTION, ON MYOELECTRIC ACTIVITY OF RABBIT ILEUM IN VIVO. C.D. Lind~ R.H. Davis~ R.L. Guerrant~ J.E. Kaper~ and J.R. Mathias. U. of Virginia, Charlottesville, VA 22908 U.S.A. Vibrio cholerae and its heat-labile enterotoxin, choleragen, induce in ligated intestinal loops of anesthetized rabbits distinct effects on the myoelectric activity characterized by the migrating action potential complex (MAPC) (J Clin Invest 58:91, 1976). Choleragen also induces secretion and is thought to work through a cyclic-nucleotide-dependent pathway stimulated by the A subunit of the toxin. Recently, recombinant strains of V. choleras, which produce no subunit of cholera t~xin (CT-A-B-) or the inactive binding subunit only (CT-A-B ~) have been developed for a live oral vaccine. These live vaccines induce immunity to V. cholerae in 90% of patients, but they also induce diarrhea in 50% (Nature 308: 655, 1984). We studied the effects of these recombinant strains on rabbit ileum by using myoelectric recording techniques. An acute anesthetized rabbit model was used with 7 Ag-AgCI monopolar electrodes at 2.5-cm intervals; 3 electrodes were sewn onto the serosal surface grad to a terminal ileal ligated loop and 4 onto the loop. One of 4 treatments (i ml) was injected into the loop, and the myoelectric activity of each rabbit (n=5 for each treatmen$)+was recorded for at least 8 ~: i) E1 Tor wild type, CT&A B ; 2) strain~ CVD 106, CT-A-B-; 3) strain JBK 70, CT-A-B- (there were i0~ organisms each); 4) sterile culture broth. Results: CT-A+B+ MAPCs

42.6 -+ 17.7

~values represent

CT-A-B+

CT-A-B-

Control

0,4 -+ 0.4

0,2 +- 0.2

2.0 + 2.0

t h e mean +- SFA,I/8 h / r a b b i t ;

** p < 0,02

Conclusions: i) The myoelectric effects induced by V. cholerae and its enterotoxin were not induced by CVD 106 and JBK 70. 2) Diarrhea induced by these strains does not appear to be secondary to motility changes produced by the holotoxin. Other possible mechanisms for diarrhea in these patients may be bacterial colonization or the production of an as-yet-unrecognized toxin by these recombinant strains. (A-19)

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Digestive D~eases and Sciences, Vol. 32, No. 8 (August 198~

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY CHANGES OF COLONIC MYOELECTRIC ACTIVITY IN IRRITABLE BOWEL SYNDROME (IBS): INFLUENCE O F RECORDING SITE AND METHOD OF ANALYSIS. K.L6ffler, R.H61zl, C.Kr6ger, L.P.Erasmus & W.E.Whitehea--d-?. Max-Planck-Institute of Psychiatry, Dept. of Psychology, Munich, West Germany, and Johns Hopkins School of Medicine, Baltimore, U.S.A. Previous reports on colonic myoelectrical activity in IBS are contradictory. The present study investigates the hypothesis that this is due to methodological influences. SW and motor activity of the rectum and sigmoid was recorded in 11 healthy controls and 44 IBS patients with predominant diarrhea (D; N=14), predominant obstipation (0; N= 12), or alternatihg symptoms (A; N=18). Recordings were taken under baseline and after a 500 kcal testmeal. SW's were recorded with ring and suction electrodes, pressure with open-tip catheters and a n a i r - f i l l e d latex balloon. All records were analysed by means of automatic wave recognition and spectral analysis. Signal intensity was measured by mean power, mean wave-amplitude, motility index and spectral power in frequency bands 2-4 and 5-12 cpm resp.; signal structure was evaluated by number of waves of different duration (d ~ 1 5 sec., d < 15 sec.) and relative spectral power (RSP) of 2-4 and 5-12 cpm activity. Statistical maalysis was performed by MANOVA or non-parametric tests (level of significance p < 0.05 throughout). All intensity measures gave identical results: sigmoid pressure increased while rectal pressure decreased after the test m e a l ; S W intensity was not affected. Neither the number of waves nor RSP of pressure recordings were altered in IBS-patients. In contrast SW structure shows significant group differences depending on recording site: In the control group 2-4 cpm RSP drops while 5-12 cpm RSP and number of short waves rise after the meal. This indicates a postprandial shift toward higher frequencies. No such shift could be observed in D-patients, and A- and O-patients exhibited a shift in the opposite direction. Number o f long waves and 2-4 cpm RSP of rectal SW~s were significantly lower in patients than in controls while number of short waves and 5-12 cpm RSP did not differ. These results suggest changes of myoelectric activity in IBS that may be found only in SW structure and depend on recording site.

ANGIOTENSIN II - A POTENT STIMULANT OF HUMAN GASTRIC SMOOTH MUSCLE F~E. L~idtk% K. Golenhofen* and F. Schubert Department of General Surgery, D-3#00 GEttingen, FRG; *Department of Physiology, D-3550 Marburg/Lahn, FRG. Angiotensin lI (ANG) has been demonstrated to have an excitatory effect on isolated smooth muscle of small intestine and colon (cat, guinea-pig, rat). For a precise analysis of ANG effects on human gastric muscle we dissected longitudinal (io) and circular (c[) strips from fundus (Fu), corpus (Co), antrum (Aft) and duodenum, and circular muscle from the inner and outer part of the pyloric sphincter (Py-inn and Py-out). The mechanical activity of these muscle strips was recorded simultaneously under auXotonic conditions. Preparations were taken irom a total of 10 stomachs (from organ donors or gastrectomy preparations). Results= Excitatory effects a f t e r applicatiofi of ANG (10-9-10 -6 mo17~ were regularly observed in all types oi preparation (threshold: 10-9 tool/l). The quality of the responses depended on the general characteristics of the special preparation. Tonic types of muscle showed predominantly tonic responses to ANG (Fu-io, Fu-ci, Co-Io). Purely phasic muscles (An-ci) showed increases os the phasic activity to ANG (amplitude up to #0% k i), Intermediate types of muscle exhibited combined phasic-tonic responses (Co-ci, An-lo). Strong phasic responses were also seen in Py-out, weaker responses in Py-inn. Phasic-tonic activations were observed in the duodenal preparations, accompanied by slight increases in frequency. The intensity of the ANG-induced responses often exceeded the maximum acetylcholine-induced activation. The whole pattern of ANG responses was similar to bombesin-induced activation. Atropine 10-5 mol/l and tetrodotoxin i0 -6 mot/1 did not abolish the ANG-induced activity which indicates a direct effect on smooth ~nuscle. Conclusions: Angiotensln II is one of the most effective stimulants of human gastric smooth muscle, which is nearly as potent as bombesin.

INTERNAL ANAL SPHINCTER DAMAGE IN NEUROGENIC FAECAL INCONTINENCE. D.Z~ Lubowski~ R.J. Nicholls, D.E. Burleigh, M. Swash. St. M&rk's Hospital, City Road, London ECI.

VOLTAGE-DEPENDENT ACTIVATION OF CALCIUM CHANNELS IN RABBIT JEJUNUM. I. MacKenzie~ P.I. Aaronson a n d T.B. Bolto• Dept. of Pharmacology, St.George's Hospital Medical School, London S.W.17 ORE, U.K. The excitatory actions of neurofransmitters and other modulatory influences on the inherent electrical activity of the gastrointestinal tract are crucially dependent upon the contribution of extracellular calcium influx into the smooth muscle Cells. In the present experiments, we have isolated single cells from the longitudinal muscle of rabbit jejunum by enzymic digestion and used patch-clamp recording techniques to measure such calcium current directly under voltage cla~p. Calci~ currents (leakcorrected) were recorded (in solutions containing 1.5ntM Ca 2+) when the cells were held at relatively negative holding potentials (-60 to -90mY) and stepped to more depolarized test potentials. With a holding potential of -70mV, the threshold for current development was about -50mV, and a maximal peak current of 200pA was attained at -10mV; the current reversed about +40mV. During a test pulse of 500ms, appproximately 90 % of the peak current was inactivated. Current was almost completely available at a holding potential of -60mV (which approximates to cell resting membrane potential), was half available about -45mV and was completely inactivated at potentials more positive than -30mY. The currents were larger in the presence of elevated extracellular calcium concentrations, while their peak amplitude was reduced and their inactivation was slowed in the presence of barium ions (5mM). Currents were approximately doubled in magnitude by the addition of the calcium entry promoter Bay K 8644 (I#M). Both the dihydropyridine nifedipine (0.01-1~M) and nickel ion (50-500uM) produced concentration-dependent antagonism of peak and sustained currents. TheSe intestinal calcium currents are larger, but qualitatively similar to those observed in similar experiments in arterial smooth muscle cells, and may reflect a higher current density in jejunal cells. Selective pharmacological modification of either peak or sustained current components would extend the hypothesis of multiple calcium channels to gastrointestinal smooth muscle.

In neurogenic faecal incontinence there is denervation of the pelvic floor muscles. We have investigated internal anal sphincter (IAS) function in patients with neurogenic incontinence to assess whether damage to this muscle has also occurred. Six female patients undergoing postanal repair (PAR) for major neurogenic faecal incontinence had preoperative anal manometry, measurement of perineal descent, pudendal nerve terminal motor latency, single fibre EMG of the external sphincter and surface recording of IAS EMG. At operation a biopsy was taken from the lower edge of the IAS for in-vitro study to test myogenic tone (response to noradrenaline and isoprenaline) and activation of neural elements (response to electrical field stimulation (EFS) and dimethylphenylpiperazinium (DMPP)). Electron microscopy was carried out on each specimen. Seven patients with normal continence, undergoing rectal excision were used as control subjects. All PAR subjects and no controls had evidence of pudendal neuropathy. IAS EMG showed no activity in 4/6 PAR subjects; in two, and in 6/7 controls slow waves of frequency 20-40/ mln were present. IAS muscle strips f r o m all control subjects showed normal responses, muscle strips from PAR showed complete insensitivity except in two subjects where there was contraction to noradrenaline and relaxation to isoprenaline. Electron microscopy showed normal IAS in 6 control subjects and minor changes in one. All PAR subjects showed varying degrees of atrophy and necrosis of smooth muscle cells which were separated by collagenised connective tissue. These findings indicate that in neurogenic faecal incontinence there is also IAS damage.

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY PYLORIC CONTROL OF THE MIGRATING MOTOR COMPLEX IN SHEEP. C.H. Malbert and Y. Ruckebusch. Ecole Nationale V@t@rinaire, 31076 Toulouse, France. The migrating motor complex (MMC) was reset at a faster rhythm after pylorectomy in the fasted dog (Gastroenterology, 1987, 92 : in press). The aim of this study was to validate these effects of pylorectomy in the ruminant species for whic h the MMC recurs regardless of feeding and to clabify the possible role of the pylorus in the initiation of the MMC pattern. Eight Romanov ewes were fitted with nichrome wire electrodes along the duodenum at 5-cm intervals and curved strain gauge transducers sutured on the antrum and duodenum at 5 cm from the pylorus, A silastic tube was inserted inside the fundus to measure the gastric em'ptying rate via CrEDTA disappearance (Br. J. Nutr. 1985, 53:373). The long pyloric nerve was sectioned in two sheep, two others were submitted to a submucosel pyloroplasty. Pylorectomy was performed by excision of the p~$oric ring in two animals and the two remaining sheep served as control. The MMC intervals were 93 + i0 min (n = 36) and the mean gastric outflow 210 + 30 ml/hr in control sheep (n - 6). Section of the long pyloric nerve was unable to change the MMC frequency despite a lower but not significant gastric outflow (180 + 40 ml/hr). Pylorectomy drastically enhanced the MMC frequency by 6 1 % (36.4 + 9 min) at all the levels of the duodenum, although without changes in the velocity of propagation of the phases [II and the gastric emptying was increased by 63 % (552 + 37 ml/hr). A similar increase in gastric emptying was recorded after submucosal pyloroplasty (415 + 28 ml/hr) and was likewise associated with an increase in the MMC frequency (33 + iO min). It is concluded that the MMC pattern was reset at a faster rhythm in sheep after both pylorectomy and submucosal pyloroplasty. The results suggest that the flow rate of digesta has a major role in the initiation of the MMC pattern in sheep.

THE EFFECTS OF SOMATOSTATIN ON SIMULTANEOUS MEBSUREMENTS OF GRLLBLROOER VOLUME AND SMALL INTESTINRL MOTOR RCTIVITY IN HUMAN SUBJECTS L.MarziQ, M.Neri, ~.Cspone, C.DeSnqelie, M.OeCarne.!~tituts di Fisiopatolsgla Me~Ica,Universita' di Chleti,CHIETI,IT6LY. In this study,we have examined the ab~lliy of somatostatln t o c o n v e r t Motility pattern5 o f gellblaOder and proximal duodenum from the po~tprand!ai ~o interdlgestlve, We ~imultaneously recorded gel/bleeder volume (GSV) and small intestinal ~otoc activity in four" healthy subjects.lntestinal motor activity wa~ Pecorded ~anemetrically and 6BV was Monitored by real-time ultrasonagrapny by the Method of Ever~on .Aliowing an overnlgn~ faet,t~o consecutive phase Ill inierdige0tLve molor cople• (IDMC) were recorsed.6 standard Meal (}@78 Keel)was then given and recordings com%inued until a typical postprandial MOtility ~as observed. Somatostatln (@,@5 9g/Kg/Hr) ~as infused for 15@ Minutes since 3@ minutes after the initiation of the fed motor pattern. GSU was mqmltoreo every S mlh during thi~ protocol. [n each subject,lnfusion of somatost@tin ~nter?upted the postdrandial motility p a t t e r n by rapidly !ndu~ing ~hase III-llks motor complexes. These were followed by a motility pattern which closely resembled that which followed the spontaneous pn6se rll comple~es recorded prior to %he meal. The 5omatostatln lhduced MOtOr soMplexe~ where indistinguishable from the spontaneous one~. Moreover, a second motor complex occurred OurlnQ somato~tatln infusion ~t an interval predicted on ~he heal5 of the spontaneously occurring motor complexes. 6t the end of somatostatln Infuslon the reappearance of ~ne fed pattern was noted. 6s expeczed,gallbladder volu~es decreased immediately p r i o r t o ssontaneous phase Ill intestinal Motor complexes,and there was a more sustained decrease after the meal. Somatostatin ~n~uslon caused an increase in the postprs~dlal gallbiasser volume to vaiue~ which exceeded those oosehved in %he fasting state. These results raise the possibility that

C O M P A R I S O N OF M E A S U R E M E N T S OF G A S T R I C E M P T Y I N G USING E P I G A S T R I C I M P E D A N C E AND A P P L I E D P O T E N T I A L T O M O G N A P H Y . Y.F. Mangnall, B. Brown, D.C. Barber, N.W. Read, and A.G. Johnson. Department of Surgery, Medical Physics and Physiology, University of Sheffield, Sheffield, U.K. Two new systems have recently been described which use changes in epigastric impedance to follow gastric emptying (Gut 1985; 26: 607 and Gastroenterology 1987 - in press). I n i t i a l c o m p a r i s b n s of the 2 m e t h o d s w e r e c o n d u c t e d invitro u s i n g an oval p e r s p e x tank filled w i t h saline to simulate the human torso, and rods of varying diameter to s i m u l a t e the stomach. M e a s u r e m e n t s o b t a i n e d w i t h both methods correlated well with the square of the radius of the glass rod placed in the centre of the tank (r = 0.99). H o w e v e r , the i m p e d a n c e e p i g a s t r o g r a p h v a l u e s i n c r e a s e d m a r k e d l y if the rod was m o v e d a n t e r i o r l y in the tank, w h e r e a s v a l u e s obtained by A P T w e r e unchanged. This suggested that ~ovem'ent of a m e a l l a t e r a l l y w o u l d i n f l u e n c e the e p i g a s t r o g r s p h results but not the APT reaults~ The rate of emptying of beef soup was studied by both m e t h o d s in v o l u n t e e r s w h o s e g a s t r i c a c i d s e c r e t i o n was i n h i b i t e d b y cim~etidlne (800mg), and the r e s u l t s compared with~those obtained simultaneously by scintigraphy. The profile of gastric emptying measured b[ APT was similar to that obtained by scintigraphy (r for t2 from s c i n t i g r a p h y vs APT = 0.80; p0.1). The r e p r o d u c i b i l i t y of the results o b t a i n e d by i m p e d a n c e ePigastrography and APT was studied by following t h e r a t e of e m p t y i n g of ah oxo drink on two c o n s e c u t i v e days. There was a strong correlation between the half emptying times m e a s u r e d by APT on the two o c c a s i o n s (r = 0.88, p0.1). Neither method was able to f o l l o w g a s t r i c e m p t y i n g a c c u r a t e l y if g a s t r i c acid secretion was not inhibited by cimetidine. In conclusion, our results show that APT gives m o r e a c c u r a t e and reproducible results than the i m p e d a n c e e p i g a s t r o g r a p h .

motil~ty patterns interdigeStlve s t a t e

somatostatin

May

be

involved in the conversion from the postprandial in these reDlons,

of

~o

TWO TYPES OF K + CHANNELS IN M A M M A L I A N COLONIC MYOCYTES. E A M a y e r , HW Kao, WJ S h a p e , Jr, C T Hsu. Department of M e d i c i n e , Harbor-UCLA Medical Center , Torrance, CA, 9 0 5 0 9 . The activation of c o l o n i c s m o o t h m u s c l e by neuropeptides involves modulation of a K + conductance. We s o u g h t to c h a r a c t e r i z e this conductance in r a b b i t c o l o n i c m u s c l e u s i n g the patch clamp technique. Single myocytes from c i r c u l a r and l o n g i t u d i n a l muscle were prepared using a collagenase dispersion m e t h o d and s t u d i e d in cell a t t a c h e d and e x c i s e d i n s i d e out patches. Results: Using high resistance pipettes (5-10 Megaohms), up to 5 K + c h a n n e l s w e r e s e e n per p a t c h . In a s y m m e t r i c K + solutions ([K] n 6mM: [K] i 1 2 6 m M ) two t y p e s of v o l t a g e sens~tlve K + c~annels were seen. Reversal potential measurements indicated that both channels were highly selective f o r K o v e r Na ( P k / P N ^ >> 10) a n d w e r e p a r t i a l l y inhibited by tetrae~hylammonium (20mM). The smaller Channel had a c o n d u c t a n c e of 48 pS and t h e l a r g e r channel a conductance of 105 pS ( n = 6 ) . In symmetric K + gradients ([K] 1 2 6 m M ) o n l y t h e large channelwas seen. Under these conditions it s h o w e d a l i n e a r I - V r e l a t i o n s h i p between - 6 0 m V and + 60 m V and a s l o p e c o n d u c t a n c e of 201 + 35 pS ( n = 1 0 ) . In i n s i d e out p a t c h e s , o n l y t h e open probability of t h e l a r g e c h a n n ~ l w a s increased by i n c r e a s i n g the b a t h Ca K+ f r o m 5nM to 5 0 0 n M . W h e n b a t h Ca 2+ W a s g r e a t e r t h a n 50uM, t h i s c h a n n e l Was f u l l y a c t i v a t e d and c o u l d not be f u r t h e r a c t i v a t e d by d e p o l a r i z a t i o n . Conclusion: Rabbit cblonie muscle contains two c l a s s e s of K + c h a n n e l s w h i c h a p p e a r to be activated by d i f f e r e n t intraceilular mechanisms. Modulation of t h e s e c h a n n e l s m a y c o n t r i b u t e to agonist-indueed c h a n g e s in c o l o n i c c o n t r a c t i o n .

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY GRADED ANAL SPHINCTER RELAXATION: AN INTERNAL SPHINCTER PHENOMENON. S.McHugh; K.Walma; N.Diamant. University of Toronto, Toronto, Ontario, Canada. We further explored the concept that the anorectal sampling reflex is due primarily to graded relaxation of the internal anal sphincter (IAS), rather than to proximal IAS relaxation and distalexternal anal sphincter (EAS) contraction Normally , there are s e x and age-related differences in the sphincter relaxation response to rectal distension. Therefore 103 female subjects < 60 years of age were studied: 57 healthy volunteers with normal voluntary EAS contraction. (V+); 6 healthy volunteers with inability to voluntarily increase resting anal pressure (RAP) by > 20 mmHg (VO); 20 patients with fecal incontinence (FI) and 20 constipated patients (C), all lacking ability to increase RAP. Detailed sphincteric studies were performed using a perfused catheter system. The presence or absence of a rectoanal contractile reflex (RACR) was scored using standardized criteria, Data were taken for the posterior anal canal axis only and were standardized and plotted using interpolation techniques. Results: On intra-rectal balloon distension, graded relaxation of the anal sphincter was seen in all subject groups. In normal (V+) volunteers , the maximum residual pressure (MI~p) for the posterior axis coorelated with residual pressure for all axis (R 0.79, P < 0.0005). The MRP occurred at 70-75% of the sphincter length from the rectum in all groups, MRP expressed as a percentage of the peak resting anal pressure was identical for V+ volunteers (42%), VO volunteers (44%), and constipated patients (41%). However, this residual pressure was lower in the patients with fecal incontinence (32%)~ The presence or absence of an RACR in subjects with no voluntary contractile ability did not significantly influence the relaxation profile. Conclusion: The anorectal sampling reflex which occurs in response to rectal distension presents as graded sphincteric relaxation. This occurs independent of the ability to voluntarily contract the EA$, or the presence or absence or the RACR. Therefore, the sampling reflex may in large part be an internal anal sphincter phenomenon.

TACHYKININ RECEPTOR CHARACTERISTICS OF FELINE COLONIC MUSCLE, IN VITRO. A. Merlo S. Cohen. Dept. of Medicine, Temple University School of Medicine, Philadelphia, PA Tachykinin s are a family of structurally similar natural peptides with a prompt stimuiatory effect on smooth muscle. Their role in the regulation of colonic motor function in mammals is not fully understood. The purpose of this study was to determine tachykinin receptor characteristics for feline colonic muscles isolated from different sites. Proximal longitudinal (PL), proximal circular (PC), distal longitudinal (DL), and distal circular (DO) muscles were studied under isometric conditions, in vitro. Dose-response relationships were obtained for the prototype tachykinin substance P, and its analogs kassinin, neurokinin, and physalemin. Tensions were measured at Lo, the length of optimal active tension. Responses were normalized for the maximum active tension developed by each2muscle during KOI (0.667• kg/c~ in PL, 0.392i.008 kg/c~ in PC, 1.354• kg/cm in DL, 0.381• kg/cm in DC; mean• The tachykinins varied in potency and efficacy for each muscle. Physalemin was the most potent (ED50-5xI0"9M) and efficacious agent for DL muscles, generating 99% maximum tension (p
IF~dUNOHISTOCHEMISTRY OF GANGLIONATED PLEXUSSES AND OF MOTOR AND SENSORY PATHWAYS IN THE HUMAN OESOPHAGUS. J. Mebis~ K. Geboes~ J. Janssens I V. Desmet and G. Vantrappen. Lab. Histo- & Oytcehemie~ Dept. Med. Res.~ K.U.Leuven~ Belgium. Unlike in the animal~ the microanatomy of the intrinsic innervation~ particularly the intramural motor and sensory pathways, are poorly known in the oesophagus of man. We stained total organ specimens immunohistochemically for S-I00 proteic (Schwann cells), Neuron ~peeifie Enolase (~erve cells), Neuro-Filaments (neuronal eytoskeleton) and MYelin B__asic llrotein [myelinated nerves). Staining for S100, NSE and NF reveals in detail the organisation of the myenteric plexus. From pharynx to eardia the plexus is composed of primary, secondary and tertiary fascicles, containing intrafascicular, intermediate and parafascicular ganglia. Within these ganglia NF-stains reveal : - Dogiel type I and II ganglion cells with characteristic axons and dendrites; - Nerve fibers bearing varicose thickenings and club- or budelike endings; - rare intraganglionic laminar nerve endings. In the striated muscle segments. MBPstaining reveals extensions Of the pharyngeal plexus and branches of the recurrent laryngeal nerves. These traverse the myenteric plexus through the ganglia and terminate on striated muscle cells. At these sites NF-stains reveal clusters of motor endplates. Neuromuscular spindles, and complex, richly innervated structures, staining for MBP and NF a~e present. Myelinated nerves within branches of the peri-oesophageal vagal plexus can be followed throughout the myenteric network of the smooth muscle segments until MBP-positivity is suddenly lost in the ganglia. As in the animal oesophagus these myelinated nerves may terminate in sensory endings. A submucosal ganglionated plexus with complex sensory receptors is demonstrable. These immunohist0chemical findings allow a detailed analysis of : I) the micro-anatomy of the intrinsic innervation of the human oesnphagus~ 2) the intramural pathways of the motor innervation of the striated muscles; 3) neural structures representing sensory receptors within the musculosa and submUcnsa.

CEREBRAL EVOKED POTENTIALS AFTER ENDORECTAL MECHANICAL S T I M U L A T / O N S IN H U M A N S . P.Meunier L.Collet, R.Duclaux, S.Chery-Croze. INSERM U45 et Laboratoire de Physiologic Sensorie]/e, Univereit~ Lyon ~ Lyon, Frances

depolarization

Although numerous clinical studies have proved that an imDaired rectal sensation is a major factor in fecal continence dysfunctions, ob~=ctlve studies in this field are still lacking. To Drov~de information on the normal rectal afferencles, a study of cerebral potentials evoked by mechanical s~mulation of the rectal wall was carried out in i0 healthy volunteers (5 M, 5 F ; 33 to 52 yr). The stimulating device consisted of a rectal balloon rythmically inflated and deflated by means of an animal breathing ventilater. Recordings were obtained 2 c m behind the vertex (C'z). The responses were averged from 300 to 800 sweeps. The average was ~ g g e r e d either on inflation ("on" effect) or on deflation ("off" effect L Inflation volume and pressure were adjusted to induce a c/ear not painful pu]slng sensat/on. Reproducible responses were recorded by both "on" and "off" effectS. The evoked potentials Were polyphasic with a succession of positive and negative waves (peak latencies between 78 and 310 ms). The shape of the response was perfectly reproducible in the same sub~zt ; morPhology , latencies and amplitudes seemed to he an individual cheracteristic. Intersub~ct variability was displayed : only the early waves (latency<100 ms) were reproducible, late waves exhibited variable latencies and morohology. The present ~ndings are the f/rst demonstration of the poss/hility of recording an evoked potential on the scald after a mechanical stimulation of the rectum.

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY INTERSTITIAL CELL5 OF CAJAL, ENTERDGLIAL CELLS, MACROPHAGELIKE CELLS: PROBLEMSOF IDENTIFICATION. H.B. Mikkelsen, Lfhuneber 9 and O. Hussein. Univ. Copenhagen, Anat.Dept. O, Panum Instituttet, DK12200 Copenhagen M, Denmark. Current evidence supports a regulatory role of interstitial cells of Cajal (ICC) in esophageal and GI motility. A major problem is bhe unambiguous identification of ICC, which still depends on the combined use of basically nonspecific methods (supravital methylene blue (MB); zinc iodide/osmic arid (ZIO); electron microscopy). M8 and ZIO may or may not produce a selective staining of IOC, nerveplexuses or both, the results being highly dependent on the handling of the tissue prior to incubation ~ith the dye. Incubation of the excised gut nearly always results in a complex mixture of staining patterns. Using the small intestines from mice, rats and guinea pigs (newborn to adult age), we have further developed the MB method to Facilitate the nearly-selective (a few axons co-stain) staining of the entire network of ICC associated with Auerbaeh's p]exus (ICC-AP). This recent modification (of. Adv. Anat.Embryol. Cell Biol. 1982, 71:i) involves s short (]-i0 minutes, depending on animal age and tissue thickness) pre-ineubatio 9 of the whole intestine with s high eoncentrat'ion (SxlO -~ M) of lyso-leeithin in a Ca-free medium. A visible effect of this treatment is the destruction of a mesothelial diffusion barrier. Uith this method ~e demonstrate: (i) 7he distribution of a network of ICC-AP throughout the small intestine, and its evolution with age; (ii) A clear distinction, also in guinea 'pig, between ICE-AP and enteroglial cells (cf. the recent claim iArch. Histol.Jsp. 1986, 49:159) that ICC-AP are a type of enteroglial cells, supposed to be S-IO0 protein positive). (iii) By a double-labelling technique (MB For ICC-AP, combined with uptake of Fluorescence-labelled dextran by maerophage-like cello (MLC-AP)) we demonstrate the regular and constant arrangement of both cell types. In particular, me wish to call attention to t h e MLC-AP as a cell type of constant and regular distribution, exhibiting close contact over large membrane areas with putative pacemakers (ICC-AP) = but of unknown function (secretory? prostaglandins? Cf. Anat. Ree. 1985, 213:77).

PUTATIVE INHIBITORY TRANSMITTERS IN THE GUINEA PIG INTERNAL ANAL SPHINCTER. T.C. Muir and A. Anne S t i r r a t . Department of Pharmacology, U n i v e r s i t y of Glasgow, Glasgow Gl2 8QQ, U.K. Substances proposed as neuretransmitters must mimic the response to nerve stimulation at the neuroeffector junction concerned. The a b i l i t y of adenosine triphosphate (ATP) and several peptides to mimic the e l e c t r i c a l response to stimulation of intramural non-adrenergic, non-cholinergic (NANC) nerves has been compared in the guinea pig internal anal sphincter (gpias, resting Em = 41 • 4.63 S.D. ). The responses to nerve stimulation and drugs were measured i n t r a c e l l u l a r l y with glass microelectrodes (20-40 megaohms), f i l l e d with KCI (3M). To minimize Igss and ensure t h e i r discrete l o c a l i z a t i o n to the recording s i t e , drugs were applied by pressure ejection at 40 psi (Picospritzer General Valve Corporation, N.J., U.S.A.) from a broken o f f microelectrode (O.D. 2 pm-lO pm} rather than by i n j e c t i o n into the bathing f l u i d . Mechanical responses to nerve stimulation were measured by force displacement transducer. Field stimulation (single pulse and 5 pulses at 5, lO & 20 Hz, 0.5 ms supramaximal voltage) evoked i n h i b i t o r y junction potentials and relaxed the sphincter. ATP (lO-JM, 25-55 ms application) i n h i b i t e d the frequency and amplitude of spontaneous spike discharge and hyperpolarized the membrane. The rate of onset of the hyperpolarization was comparable to t h a t of nerve stimulation. Bradykinin (lO-6-10-3M) reduced spike discharge; the membrane was hyperpolarized but only gradually and at a rate not comparable to that of nerve stimulation. Somatostatin (IO-5M-IO-3M), neuropeptide Y (lO-5M) and Vasoactive i n t e s t i n a l polypeptide (VIP, lO-7MlO-5M) were, l i k e saline (0.9%) i n e f f e c t i v e although VIP (lO-7M) on occasion produced delayed membrane hyperpolarizations some 7 sec a f t e r application. The results show that the response of the gpias to ATP most closely resembles that to stimulation of NANC nerves, i t seems u n l i k e l y that any of the peptides investigated has a t r a n s m i t t e r function in t h i s tissue. The support of the SERC, the Wellcome Foundation, Pfizer Central Research and Glasgow U n i v e r s i t y Medical Research funds is g r a t e f u l l y acknowledged.

ENDOGENOUS AND EXOGENOUS PRI;~ARY PROSTAGLANDINS ENHANCE i{USCARINIC RESPONSES IN CIRCULAR 81400TH ~IUSCLE CELLS OF THE RABBIT CAECUi,I. K. NAXAO, K. EITA~URA and B. KURIYAIIA, Dept. of Pharmac., Fac. of Hed., Kyushu Univ., Fukuoka 812, Japan. Effects of PGE2, PGFI~ and indomethacin on electrical and mechanical responses evoked by transmural stimulation or exogeneous application of ACt were investigated using circular smooth muscle cell of the rabbit terminal caecum. Transmural stimulation provoked excitatory junction potential (e.j.p.) with contraction. Both responses were inhibited by atropine or tetrodotoxin. Indomethacin (below SO ~[) neither modified the resting membrane potential nor muscle tone. but amplitudes of the twitch contraction and e.J.p, were inhibited in a dose dependent manner. Low PGE 9 (below 1 n;/) neither altered the membrane potential nor the muscle tone, while high PGE 2 (above iO ~ ) contracted the tissue without depolarization of the membrane in the presence of SO ~N indomethacin. PGE2 prevented inhibitions of the contraction and e.J.p, evoked by field stimulation during preapplication of indomethaein. Exogenous application of ASh (0.I - O.3 ~ ) depolarized the membrane and produced the contraction, in a dose dependent manner. The depolarization-induced by ACh was blocked b y atropine, and was partly inhibited by pre-application of indo[nethacin. PGE 2 (0.i - i00 n?~) prevented the inhibitory actions of SO ~[~ indomethacin on the depolarization induced by 0.i - 0.3 p~[ ACh. These concentrations of PGE or indomethacin did not alter 2 the the K-induced depolarization, but did slightly modify the amplitude of contraction. PGF_ (0.i - i00 nET) had actions similar to those of a~GE2 on the eholinergic responses of smooth muscles, but the potency was weaker. A synthetic thromboxane A (0.i 2 i00 n~) had no effect on the electrical and mechanical responses. Thus, primary PGs accelerate cholinergic neurotransmission by increasing the release of ASh at nerve terminals and sensitize the post-june tional musoarinic receptor to ASh. These actions of PGs on cholinergic transmissions in the caecum differ from those on mascular and tracheal tissues.

INTERDIGESTIVE G~Lr.RTADD~ MOTILITY AND BILE ACID OtK[?UT IN THE DOG. C.V. Nally, L.J. McMullin, A.S. Clabachan t G.W. Scott. Departments of Surgery & Pharmacology, University of Alberta, Canada. Both periodic contraction of the gallbladder a n d fluctuation in the rate of hepatic secretion have been suggested as possible mechanisms for the phasic output of bile during fasting; in this canine study the output of bile acids from each of these sources was quantified and correlated with pressure changes in the biliary tract during each phase of the int@rdigestive cycle. Five dogs were surgically prepared with catheters in the gallbladder, common bile duct (CBD) and duodenum, and electrodes were attached to the small intestine. Three weeks later each dog was studied in the conscious fasted state. A double marker technique was used to measure bile acid output from the gallbladder and liver into the duodenum while intraluminal pressure in the gallbladder and CBD and electrical activity in the small bowel were ~n~ored.

Pressure (ca H20 ) Gallbladder Ce~m~)n Bile Duct

Phase I

Phase 2

7.3_+0.9 6.2_+I .3

8.1+0.9" 7.3+I .4*

Bile Acids (~nol/min) Gallbladder 3.9+0.7 _ H e p a t i c 6.0+--1.9 (Mean_+S~M)

Phase 3

Phase 4

9.3_+1.0 8.1+1.5

6.7_+0.6* 5.9_+I .3*

9.8+I _ 9 0** 13.9+1.7 6.9+--I.7 6.8+T.9

8.4+1.8" 5.5+-1.9

* p<0,O5

**p<0.005

Gallbladder and CBD pressure, and gallbladder bile acid output fluctuated with the interdigestive cycle rising significantly between phases I and 2 and falling significantly between phases 3 and 4. In contrast hepatic secretion of bile acids directly into the duodenum remained fairly constant throughout the cycle. Periodic contraction of the gallbladder would therefore appear to be the principal mechanism for the phasic output of bile acids during fasting.

(A-23)

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Digestive Diseases and Sciences, Vol. 32, No. 8 (August 1987)

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY RAT SVALLINTESTINALISOGRAFTS HAVE~ FASTEDAND FED W/fOELECTRIC ACTIVITYAND DELTRFASI~) ABSORPTIVE CAPACITY. M.A. Nemeth, M.S. Harris, K. Rarr~swamy, W.H. Schraut, S.K. Sarna, R.E. Condon and G.L. Telford. Departments of Surgery and Medicine, Medical College of Wisconsin and Clement J. Zablocki Veterans Administration Medical Center, Milwaukee, WI 53226 and Department of Surgery, University of Chicago, Chicago, IL 60637, U.S.A. Intestinal transplants are being performed in humans in spite of minimal information about the effect of transplantation on intestinal motility and absorption. Small intestinal isografts of jejunoileumwere performed using inbred Le~is rats (N-4). Since inbred rats do not reject transplants from rats of the same strain, it is possible to study the effect of transplantation alone without giving irnnunosnppressive drugs. After recovery bipolar electrodes were sutured to the native duodenum and the transplanted intestine. Fasted and fed myoelectric activity and the absorptive capacity were studied. Intact Lewis rats (N=6) with a similar array of electrodes served as controls. The small intestine of control and transplanted rats had normal patterns of fed and fasted myoelectric activ!ty. Migrating myoelectric complexes (MV!Cs) occurred in both the native duodenum and the transplanted intestine and were interrupted by feeding. MVI2cycle times in the native duodenum in controls were 20.6 + 2.9 min (X'+ SD) and transplanted rats 28.1 + 9.0 (p ~ 0 . i ) . MgCcyele times in the transplanted bowel was 14.7 + 3.0 and in the control jejunum 17.3 + 4.3 (p > 0.1). Single pass perfnsion of transplanted jejunum demonstrated a 35 - 40% decrease in absorption of glucose and electrolytes comparedwith controls. We conclude: (1) that rat small intestinal isografts have fed and fasted myoelectric activity that is similar to controls and that therefore if rejection is controlled intestinal allografts should have normal rmyoelectric activity; and (2) since isografts have a decreased absorptive capacity, greater lengths of intestine will need to be transplanted in a clinical model.

NEUROPEPTIDE Y AUGMENTS ADRENERGIC CONTRACTION OF THE FELINE LOWER ESOPHAGEAL SPHINCTER. H. Parkman, K. Kisoak, C. Ogorek, A. Lambroza and J. Reymolds. University of Pennsylvania, Philadelphia, PA 19104-4283, U.S.A. Neuropeptide Y-like immunoreactivity (NPY-LI) has been localized in the myenteric plexus and smooth muscle of the gastroesophageal junction. NPY is often co-localized with catecholamine transmitters. NPY inhibits ileal smooth muscle, but its effect on sphincteric muscles has not been examined. Aims: i) To investigate the effect of NPY on the feline lower esophageal sphincter (LES) in vivo, 2) To determine if NPY influences phenylephrine or bethanechol (BETH)-induced LES contraction, and 3) To define the innervation of NPY at the LES by immunofl~orescence. Methods: LES and esophageal pressures were recorded by a fixed perfused catheter assembly in anesthetized cats. Peptides were infused via the left gastric artery. In separate eats, the LES was determined manometrically and stained for NPY LI with appropriate controls. Results: Indirect immunofluorescence revealed intense staining for NPY-LI in the circular muscle and muscularis mncosa of the LE5. Staining was also present in longitudinal muscle and myenterie plexus of the LES. In vivo, NPY had a biphasic effect on LES pressure (LESP) characterized by a similar threshold, ED-S0 and maximal doses. NPY at the ED-50 (10-6 gm/kg) produced an initial transient ( ~ 30 sec) contraction of 19,0+7.9 ~m2Mg followed by a prolonged ( ~ 3 min) decrease of baTal LESP from 35.3+5.9 to 24.0+3.8 mmHg. Propranolol and phento!amine had no influence--on either effect of NPY. Atropine decreased LESP by 27.8+7.3%, and abolished the LES contraction to a submaximal--dose of NPY (10 -5 ~l~/kg) (2.0+1.1 mmHg, p < 0.005). NPY at the threshold dose (10-7 gm/kg)--augmented the peak contraction to a submaximal dose of phenylephrine (10-6 gm/kg) from 29.3+5.8_ to 52.0~i0.2 mmHg, p < 0.025. NPY had not effect on BETH-induced contraction. Conclusions: i) There is a dense innervation of NPY-LI at the feline LES, 2) NPY has a biphasic response at the feline LES, in vivo, 3) NPY augments the LES response to phenylephrine, 4) The contractile effect of NPY at the LES is mediated by cholinergic nerves. Thus, at the LES, NPY is excitatory and can augment ~-adrenergic contractions.

GASTRIC BUT NOT SMALL INTESTINAL ACTIVITY FRONTS OF THE V~4C ARE PRECEDED BY BOTH GALL-BLADDER E~TYING AND MOTILIN RELEASE IN MAN. [~ Nilsson, T. Svenber$, T. Tollstr~m and K. Samuelson. Depts of Surgery, Clinical Physiology and Clinical Chemistry, Karolinska Hospital, Stockholm, Sweden. The relationship between fasting gall-bladder emptying, motilin release and appearance of activity fronts (AF) of the ~94C was investigated in i0 healthy volunteers. We used hepato-biliary scintigraphy in combination with manometrical measurement of gastro-intestinal motility by means of four perfused catheters. Plasma-motilin was determined by a r a d i o ~ o a s s a y . During a total registration period of 39 hours and 42 minutes we observed 19 gall-bladder emptyings, 26 metilin peaks, I0 AF with gastric components and 9 small intestinal AF. Six of the gastric AF were preceded by both gallbladder emptyings and motilin peaks. At least 3 of the remaining 4 gastric AF were preceded by biliary output and increasing or constant high motilin levels. However, these changes were neither accepted as gall-bladder emptyings, nor as motilin peaks according to our criteria. On the contrary only 1 of the 9 small intestinal A F w e r e preceded by both gall-bladder emptying and motilin release. A sharp decrease in motilin level was observed after all AF in the study. Seventeen out of 19 gall-bladder emptyings were follcmed by motilin peaks which usually occured at the end of or just after the gall-bladder emptyings. However, 7 out of 26 motilin peaks were not preceded by any gall-bladder emptyings. We conclude that fasting biliary output is closely associated with motilin release and that AF originating in the stomach but not in the small intestine are preceded by both gall-bladder emptying and motilin release.

DIFFERENT PHARMACOLOGICALBEHAVIOROF THE CANINE ILEOCECAL JUNCTIONASCOMPAREDTOTHEADJACENTILEUM ANDCOLON. P.A. Pelckmans, Y.M, Van Maercke, ~G. Herman, T.J. Verbeuren. Unlverslty of Antwerp [UIA), DlVlSlOnS at Gastroenterology ~nd Pharmacology, B-2610 Antwerpen-Wilrijk, Belgium. There is s t i l l a controversy about the existence of a sphincter mechanism at the ileocecal junction (ICJ). To i l lustrate the pharmacological profile of the canine ICJ, we compared the development of basal tension, the spontaneous activity and the effects of papaverine, t e t r o d o t o x i n (TTX), atropine, noradrenaline, acetylcholine (ACh) and electrical f i e l d stimulation (ES) on circular muscle strips of the distal ileum, the ICJ and the proximal colon. After removal of the mucosa, the strips were transferred to organ baths for isometric tension recording and placed at the optimal length-tension using ACh (2xi0-6 M). After transfer to the organ baths a basal tension developed in the ICJ (2.84• g; n=6) and to a lesser extent in the ileum (I.5,0.46 g; n=6) but not in the colon. At the ICJ the basal tension was significantly inhibited by papaverine (10-4 M). Once at the optimal point of the length-tension relationship, the three tissues showed a different pattern of spontaneous activity. The l a t t e r was most pronounced in the d i s t a l ileum and decreased towards the ICJ. At the ICJ no spontaneous a c t i v i t y was present. The colon showed intermediate spontaneous activity. Atropine (3xi0-7 M) had no effect on the tension of the three tissues. A remarkable observation was that TTX (4xlO -7 M) raised the tension in the ICJ (1.29~0.42 g; n=9) but not in the ileum and the colon. Papaverine (lO-4 M) abolished the tension developed by TTX. Noradrenaline (3xlO-5 M) caused contractions in the ileum and the ICJ but not in the colon. During contractions caused by noradrenaline and in the oresence of atrenine C3xlO-7 M), ACh (10-4 M) caused relaxationsL In the same condition ES also caused frequency dependent relaxations. TTX (4xi0-7 M) blocked the relaxations induced by ES and ACh. Hexamethonium (3xlO-6 and 3xlO-5 M) and cocaine (3xl0 -5 M) blocked the relaxations induced by ACh but not the relaxations induced by ES. We conclude that the ICJ reacts differently as compared to the ileum and the colon from a pharmacological point of view. Our data suggest the presence of a non-adrenergic non-cholinergic innervation in the ileum and the ICJ of the dog.

(A-24) Digestive Diseases and Sciences, Vol. 32, No 8 (August 1987)

923

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY THE IMMOBILE PERINEUM: PATHOPHYSIOLOGICIMPLICATIONS IN SEVERE CONSTIPATION. M. Pezim, J. Pemberton, and S. P h i l l i p s . Mayo Medical School, Rochester, MN 55905 USA. Severe constipation may be due to colonic i n e r t i a , or i n e f f e c t i v e expulsion. Patients with disorders of expulsion respond poorly to therapy, Our aim was to determine whether a simple bedside t e s t could iden--Tffy those with expulsion disorders. Methods: In 24 subjects (13 healthy controls and 11 p a t i e ~ h < 2 movements/wk) we measured perineal descent in the l e f t l ~ t e r a l position during a t t e m p t ~ We correlated t h i s with defecation h i s t o r y , colonic t r a n s i t times (Gastroent. 1987; 92:40), a balloon expulsion t e s t (Gut 1981; 22:A890), p e l v i c f l o o r function assessed by dynamic scintigraphy of the anorectal angle (Surg. Forum 1986; 37:A183) and expulsion of a r t i f i c i a l r a d i o l a b e l l e d (99mTc) s t o o l . Patients with a perineal descent < 1 cm were c l a s s i f i e d as Group A; Group B and controls had > i cm descent. Results: ~ i f ~ i g n i f ~ f r o m Gr B by t h e i r r ~ a b i l i t y to straighten the anorectal angle during attempted defecation, reduced expulsion of 9gmTc s t o o l , greater t r a c t i o n required f o r balloon expulsion, more frequent need f o r manual stool e x t r a c t i o n (5/5 vs I / 6 ) , and prolonged colonic t r a n s i t in only the r e c t o s i g moid segment. Group B behaved l i k e c o n t r o l s in a l l t e s t s except f o r prolonged t r a n s i t through the r t . and I t . colon. Descent A Stool Balloon (+SEM) angle evac. e x p u l s . Colon t r a n s i t ( h r ) Tcm) (~ (%) (g) Rt. Lt. Recto. Total GrA 0 . 5 + . i 4+4* 34+6* 590+114 t 1 2 + 2 16+12 94+17f 111+3 GrB 2.1u 19u 75u 88u 4 ~ 1 1 + 44u + 2 9 u 109u Cont 2.3u 17u 80u 126u 11u 9T2 14u 34u *P<.05 vs- GrB;- tP<.~5 vs G~B and CTnt; +P~.OO2 ~s C o n t . Conclusions: The degree of perineal descent correlated well with the defecation h i s t o r y and the more sophisticated tests of colonic and p e l v i c f l o o r f u n c t i o n . Descent of < i cm ("Immobile Perineum") was associated with an adynamic anorectal angle and impaired expulsion. This simple method i d e n t i f i e s constipated patients who respond poorly to surgery and conventional medical treatment, and f o r whom a l t e r n a t i v e therapies must be developed.

THE RELATIONSHIP BETWEEN FASTING GALL-BLADDER EMPTYING AND MIGRATING MOTOR COMPLEX. N. Qvist~ E. ~ster-J~rqensen~ L. Rasmussen, S.A. Pedersen, K. Kraqlund. Department of Surgical Gastroenterology and Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark. The relationship between fasting gall-bladder emptying and appearence of phase-III complexes of the migrating motor complex(MMC) was investigated in ten healthy male volunteers. A combined technique with hepatobiliary scintigraphy and manometrical motility recordings was utilized. Gall-bladder emptying toke place in two characteristic ways in relation to the MMC-cycle. In six subjects with a median length of the MMC-cyele of 116 minutes (range 107-170), only one event of gall-bladder emptying was observed in each MMC-cycle. It occured in ]ate phase-II io close proximity to the following phase-Ill. Median time from termination of the gall-bladder emptying to the appearence of the Following phase-III was lO minutes. In Four subjects two events of gall-bladder emptying was observed in each MMC-cycle. The median length of the MMCcycle in this group was 179 minutes (range 162-250). The first event of gall-bladder emptying toke place in phase-I or early phase-ll~ and 7-28 minutes after it had terminated, an "immature" phase-Ill of enteric origion oceured on the motility curve. This phase-III complex lasted leas than four minutes and was not followed by a true period of quiescence. The second event appeared zn late phase-IT and was Followed by a true gastroduodenal phase-liT, just as in the first group. In conclusion, emptying of the gall-bladder is followed by a phase-III complex, some of which are of gastric origion, and some of enteric origJon.

ARE DYSPEPTIC SYMPTOMS RELATED TO DISTENSION OF THE GASTRIC ANTRUM? R Ricci, I Bontempo, A La Bella, A De Tschudy, E Corazziari, A Torsoli. Cattedra di Gastroenterologia I, Universit~ di Roma, Italy Although postprandial complaints in patients with flatulent dyspepsia are usually considered secondary to delayed gastric emptying,the mechanisms underlying theae symptoms are not fully clarified.ln this study ultrasound measurements (US) of the gastric antrum volume (AV) in basal conditions and at fixed time-intervals after a test meal were performed to comparatively evaluate gastric emptying in normal control subjects and in patients with flatulent dyspepsia. AV at the onset of postprandial dyspeptic symptoms was specifically analysed. In 28 patients (M:11;F:17;mean age 36 yrs,range 28-47) with functional flatulent dyspepsia ( negative upper GI X-ray, endoscopy and ultrasonography of the abdomen) and in 20 healthy control subjects (M:10;F:lO;mean age 27 yrs,range 24-39 ),AV was measured according to a previously published method (Gastroenterology 1985, 89 : 752-759) after an overnight fasting (bas) and at 30,60,90,120,150,210,270.330 min after a 1050 kcal meal (bread: 140 g;cheese: 70 g;ham: 80 g,alimentary fibres: 3.5 g,water: 250 ml). AV (ml) in controls (C) and dyspeptics (D) is reported in the table. Basal

30'

60'

C M+SD 15_'5 78•

58•

55~20 39•

3~17

30~16 21~5

D M+SD 2/_+9* 101+_40~ 89•

77~26w 82•

87•

73•

* p
~

90'

150'

2lO'

270'

330'

62•

w

Twenty three patients presented their usual postprandial complaints 150210 min after the ingestion of the test meal.ln 20/23 patients the onset of the symptoms was temporally related to a rapid volume increase of the gastric antrum (variation vs last US measurement before onset of symptoms: delta 28.5_+20ml M+SD, range 2-82mi;% variation 44.2,~36.7,range 2-145) and was associated with the appearance of variable amounts of liquid f i l l i n g gastric antrum. In all controls and in the remaining 5 dyspeptic patients without post-prandia] complaints AV progressively decreased after meal ingestion. Data of this study confirm that gastric emptying of a test meal is delayed in dyspeptic patients and indicate that postprandial dyspeptic complaints are closely related to rapid increment of antral volume rather than to delayed gastric emptying. AMBULATORY ESOPHAGEAL MOTILITY/pH MONITORING: ANALYSIS TECHNIQUES ALTER RESULTS. JERichter, LJ Peters, GB Dalton DO Eastell. Bowman Gray Mad School, Winston Salem, NC USA Ambulatory esophageal motility/pH monitoring permits accurate detection of esophageal events during spontaneous non-cardiac chest pain (CP). However, opinions differ about the definition of CP and methods to define abnormal motility changes. Therefore, we studied 28 pts (17F, IIM, age 46) with chronic non-cardiac CP. Esophageal manomerry normal in 13 pts and abnormal in 15 pts (i0 with nntraeker esophagus) METHODS: A 4.5 man catheter was used with 2 microtransducers placed 3 and 8 cm and pH probe 5 cm above LES. Catheter attached to portable recording system allowing free activity. Pts triggered event marker for CP and recorded pain severity on increasing scale (i-i0). Two methods of analysis used to measure playback of 24 hr motility/pH data: A) CP comparedto asymptomatic baselines measured for 5 min q hour using criteria of pH < 4 and abnormal motility defined by ~ or maximum amplitude/ duration or % abnormal contractions > x + 2SO of baseline values. H) CP only compared to 10 min baseline irm~ediately before each pain event. Similar pH comparison but abnormal motility defined by x or maximum amplitude/ duration or Z abnormal contractions > x + ISE of preceding 10 min baseline. RESULTS: Total of 135 spontaneous CP events (~: 4.8/ pt) recorded. Motility analysis significantly (* p < 0.01) affected the % of abnormal esophageal events: A (Total Tracing) B (i0' Before) pH<4 15 events (11%) 15 events(ll%) abnormal motility 14 (10%) 33 (24%)* both 3 (2%) 3 (2%) neither 103 (77%) 85 (63%) Esophageal events less likely during more severe GP episodes: A) scale 1-5 (72% abnormal events) vs. scale 6-10 (28%); p < 0.001 or B) scale 1-5 (63%) vs. scale 6-10 (37%); p < 0.05. CONCLUSIONS: l)Regardless of motility analysis, majority of CP events not associated with abnormal pH/motility. 2)Method B identifies more motility related CP events but these may be false positive results. 3)Increasing severity of CP does not predict the presence of abnormal esophageal events. (A-25)

924

Digestive D~eases and Sciences, Vol. 32, No. 8 (August 198~

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY INTEGRATIVE ACTIVITY OF THE ENTERIC NERVOUS SYSTEM AT THE STOMACH LEVEL. Y, Euekebuech and C.H. Nalbert, Ecele NationaIe V@t@rinaire, 31076 Toulouse, France. The cyclical contractions which lasted 5-10 sac and were propagated along the different parts of the retieulorumen (BR} at about l-min intervals, ceased definitively afte~ vagotomy in sheep. If animals are sustained on a liquid diet, slow (50 sec) and weak synchronous contractions of the fluid-filled RR are recorded at 2-3 min intervals (J. Physiol., 198~4, 346:379). The aim of this study was the identification of the factors able to modify the periodicity of this autonomous contractile pattern of the stomach. The role of the enteric nervous system (ENS) in the initiation of these contractions was studied in 14 healthy sheep from 3 to 8 weeks after vagotomy by continuous recording of the pressure changes in the RR reservoir containing liquid diet. Distension of the HR by addition of 2 1 of liquid diet (38~ increased the frequency by 30 %, such an enhancement being prevented by hexamethonium HCI (2 mg/kg) pretreatment (Ann. M~d. V@t., 1986, 130:613). The contractions were reset at a faster rhythm following cholinergic and serotonergic stimulation using bethanechol (0.02 mg/kg) and 5hydroxytryptophan (0.~ mg/kg). Inhibition of the uptake of both noradrenaline and 5-hydroxytryptamine by Midaleipran (Neuropharmacology, 1985, 24 :1211 ) increased the frequency of these contractions by 50 % during 20:-30 min. The frequency of these autonomous contractions was also transiently increased following the injection of exepanol-HCl (Drug 8es., 1955, 35:136). These results suggest that the intrinsic contractions of the RR in the vagotomized sheep correspond to the outflow generated by the ENS in response to the processing of sensory information and that the ENS system is also responsive to drugs known to affect the central nervous as antidepressants.

METHYLENE BLUE IS NOT A SPECIFIC ANTAGONIST OF INTERSTITIAL CELLS, K. Sanders, E. Burke, R. Stevens F. Vonsalis. Department of Physiology. Univ. Nevada Seh. Medicine, Reno, NV 89557. The hypothesis that interstitial cells of Cajal (ICCs) serve as pacemaker cells in the gut is supported primarily by raorphological data. This hypothesis is difficult to test physiologically. It has been reported that methylene blue, a purportedly specific stain of ICCs, also abolishes rhythmicity. But a true cause-and-effect relationship between the staining of ICCs and the loss of rhythmicity has not been established. The effects of methylene blue may be non-specific. We tested the hypothesis that methylene blue has a direct effect on GI muscle cells. Intraeellular recordings were made from cross-sectional preparations of canine proximal colon circular muscle. Cells through the circular layer were impaled and membrane potentials ranging from -79 mV at the submucosal surface to -45 mV at the myenteric border were recorded. Slow waves decreased in amplitude as a function of distance from the submueosa. While recording from cells near the submucosal border, methylene blue, (10 -5 M) was added to the perfusate. This caused e progressive depolarization of 30-40 mVs and a loss of slow wave activity. Then the electrode was withdrawn and several cells through the thickness of the circular layer were impaled. In the presence of methylene blue resting potential was quite constant across the circular layer and slow waves were abolished. These data suggest that methylene blue has a direct affect on circular muscle cells, which is similar to the effects inhibitors of the sodium pump. Depolarization with elevated external K + also abolished slow waves. In summary methylene blue caused depolarization and loss of rhythmicity which may be due to inhibition of the sodium pump. Alternatively methylene blue may be a non-selective channel blocking agent. Methylene blue may stain ICEs, but it's effects on rhythmicity are not specifically due to it's effects on these cells. (Supported by NIL Grant AM 38717).

Digestive Diseases and Sciences, Vol, 32, No 8 (August 1987)

MDTOR ACTIVITYOF THE CECLM IN THE FASTED, FED AND EVLPTY STATES. __S'K.Sarna, K.R. Prasad and I.M. Lang. Depts. of Surg. & Physiol., Med. College of WI and VAMC,Milwal2~ee, WI 53295. We investigated motor a c t i v i t y of the cecum in the fasted, fed and empty stales to determine whether this unique blind loop has any special type of contractions and whether they are correlated with small intestinal and colonic motor complexes. Twelve strain gage transducers were surgically implanted: 2on the cecum, 2 on the ileum, i on the ileocolonic junction and 7 on the colon in 4 dogs. A perfusion catheter was implanted in the ascending colon. A4-hr control recording was made after an overnight fast and then the dogs were fed a meal, or 3.8 ] i t r e s of Colyte | was perfused through the colon at 20 ml/min. The small intestinaIMV]Cs migrated to the ileo-colonic junction (period 125 + 9 min); The co]oniemotor complexes, unrelated to ileal ~ s , started distal to the ileocolonic junction (period 38 + 5 min) and migrated caudad. Cecum did not participate in anyof these complexes. Instead, it generated giant migrating contractions (CMC). The mean amplitude of cecal giant contractions was 1.82 + 0.26 and 3.37 _+ 0.38 times larger than that of contractions during ileal and colonic MVICs respectively (p<0.05). The mean duration and period of cecal dViCwere 45 + 4 s and 70 + 7 min respectively in the fasted state, and 49-+ 65 s and-73 + 8 min in the fed state (p>0.05). Emptying of {he colon decreased CMC frequency. Most cecal (:h4Csmigratedcaudad (velocity 0.22 0.02 em/sec). There was a high correlation between the a r r i v a l of an MEC in the terminal ileum and the occurrence of a cecal giant migrating contraction. A cecal GMC occurred in 27 out of 30 cases whenMVICwas in the ileum at a mean distance of 19 + 2.1 om from the ileocolonic junction. An additional 39 (:]V~Coccurred unrelated to ileal MVICs. Conclusions: 1. Cecumhas a unique motor a c t i v i t y that is different from that of the colon and the ileum. 2. The a r r i v a l of an MVIC in the ileum triggers cecal (3V~, but they also occur independently. The CMCmay serve to periodically empty the cecal contents into the colon. The lower frequency of cecal GMCs in the empty state may be due to decreased intraluminal stimulation. 3. The GVIC~occur infrequently and unpredictably in the small intestine and the colon. Cecumseems to be the only part of the gut that regularly generates ( : ~ .

NEUROPHYSIOLOGY OF MYENTERIC NEURONS OF GUINEA PIG STOMACH M~ Scheman]~ ~ J.D. W~od. Dept. o f Physiology, Ohio State University, Columbus, OH 43210, U S A The b o d y of the g u i n e a - p i g s t o m a c h was d i s s e c t e d to e x p o s e the m y e n t e r i c plexus on fragments of longitudinal muscle. Conventional m e t h o d s of i n t r a c e l l u l a r e l e c t r i c a l r e c e r d i n g w e r e used f o r i ~ y i t r o s t u d i e s o f 180 n e u r o n s f r o m 80 animals. Resting m e m b r a n e p o t e n t i a l of the cells r a n g e d f r o m - 4 5 m Y to -71mY. The m a j o r i t y of the n e u r o n s (70%) discharged only one or two spikes during intrasomal i n j e c t i o n of d e p o l a r i z i n g c u r r e n t pulses. S o m e of the neurons (20%) discharged repetitively and 10% did not disc h a r g e d u r i n g m e m b r a n e d e p o l a r i z a t i o n . None of the cells displayed hyperpolarising a f t e r - p o t e n t i a l s in a s s o c i a t i o n with spikes. The action potentials in all neurons (60) were b l o c k e d by 0.2pM TTX. Focal e l e c t r i c a l s t i m u l a t i o n of i n t e r g n n g l i o n i o fiber tracts evoked in all n e u r o n s fast excitatory postsynaptic potentials (fEPSPa) with durations of less than 30msec. Each neuron received multiple inputs that were suppressed by 20O~M hexamethoniumj but were una f f e c t e d by atropine. The fEPSPs f o l l o w e d high s t i m u l u s frequencies (>30Hz) w i t h o u t i n d i c a t i o n s of "rundown". Spontaneous fEPSPs, that were suppressed by hexamethonium o c c u r r e d in 60% of all neurons. M i c r o a p p l i c a t i o n of A C H m i m i c k e d the fEPSP in all cells. In a minority of cells (3) ACH additionally evoked an atropine sensitive slow depolarization lasting from 3-8see. Microapplication of Substance P e v o k e d in all cells (15) a long lasting (20-45see) depolarization associated with enhanced somal excitability and increased input resistance. The agonists exerted their effects after blockade of axonal conduction in TTX (0.2pM) and a f t e r s y n a p t i c b l o c k a d e in the p r e s e n c e of e l e v a t e d Mg ++ and reduced Ca ++ i n d i c a t i n g a d i r e c t a c t i o n on the impaled neuron. These studies, which are to our knowledge the first on g a s t r i c m y e n t e r i c n e u r o n s s u g g e s t that the e n t e r i c n e r v o u s s y s t e m of the s t o m a c h is s i g n i f i c a n t l y d i f f e r e n t f r o m the intestine. This m a y Be a r e f l e c t i o n of adaptation for the specialized functions of the stomach. S u p p o r t e d by: NIH ROI D K 3 7 2 3 8 to J.D. W o o d and D e u t s c h e Forschungsgemeinschaft DFG Sche 267/i-1,1-2 to M. Schemann

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY IS THE N-TERMINAL LEU-ENKEPHALIN FRAGMENT RESPONSIBLE FOR THE CONTRACTILE ACTIVITY OF DYNORPHINS IN THE ISOLATED RAT COLON? U. scheurer r E. Drack~ F. Halter. G.I. Unit, University Hospital, Inselspital, Berne, Switzerland The d-opioid-receptor agonist leu-enkephalin produces contractions in the isolated rat colon. Dynorphin has been shown to potently relax pro-stimulated longitudinal muscle strips of the guinea pig ileum. In order to investigate the role of the N-terminal leu-enkephalis of different dynotphins on colonic motility, we studied effects of 1-6 dynotphin, 1-17 dynorphin, 3-13 dynorphin, 6-17 dynorphin, b-neoendorphin, des-Tyr-leu-enkephalin as well as N-terminal fragments of leu-enkephalin on intraluminal colonic pressure. Under standard conditions rat colonic segments were maintained in Ringer-Tyrode solution. Intraluminal pressure changes were measured by a perfusion manometric system. Test drugs (10-9-I0-3M) were added to the organ bath. The pressure response is given as the ratio between pressure response to test drugs and that of the maximum FK 33-824 (met-enkephalin analogue) stimulus (x~SEM, n=6). Resslts: A similar maximum pressure response of leu-enkephalin, i-8 and 1-17 dynorphin occurred at the same concentration (10-6M) with 0.88+0.12, 0.79+_0.08 and 0.78+0.09 respectively. 3-13 and 6-17 dynorphin were unable to significantly stimulate colonic pressure. N-terminal dipeptide of leu-enkephalin and des-tyr-leu-enkephalin produced no significant pressure increase. The N-terminal tri- and tetra-peptide of leu-enkephalin were about 1000 and i00 times less potent than leu-enkephalin. Conclusions: In the isolated rat colon, N-terminal leu-enkephalin is suggested to be responsible for the motor actions of different dynorphin@. The Tyrosin at the N-termlnus seems to trigger the motor action of leu-enkephalin and dynorphins. (The role of C-terminal extensions of the leu-enkephalin molecule has not been elucidated.) The N-termlnal tripeptide of leu-enkephalin is the smallest fragment which still exerts significant motor actions.

IDENTIFICATION OF MYOELECfRiC ACrlVlIY iN s D'F THE HUMAN STOMACH. B. Schirmer~ M. Shaffrey~ B.E. Bellahsene~ R,W. MeCallum. University of Virginia Medical Center, Charlottesville, VA 22908, U.S.A. It i s b e l i e v e d that the fundns of the human stomach is electrically silent. In order to further investigate this hypothesis, 12 patients, ranging in age from 23 to 60, underwentplacement of gastric seromuscular stainless steel recording electrodes (28 gauge cardiac pacing wires) at the time of laparotomy. Electrodes were placed on the fundus, body and ans (where possible) of the stomach. Recordings were obtained postoperatively using a modified Sensor-Medics recorder and a Thorn-EMI tape recorder for subsequent analysis. Fundic myoelectrie activity was evident in all 12 patients as follows: (Data represent the grand mean + S E M )

REGULATION OF MMC ONSET AND MIGRATION VELOCITY BY MUSCARINIC RECEPTOR SUBTYPES IN THE DOG. A. gchiavone, A. Sagrada and A. GiaehettiA Dept. of Pharmacology, Istituto

CLEARANCE AND CAPACITANCE OF THE ISOLATED GUINEA PIG DUODENUM. K. Schulze-Delrieu, B. Brown and S. Shiraz• VA Medical Center, Iowa City, IA 52240 U.S.A. The duodenum resists gastric emptying even in vitro (Gastroenterology 91: 1067, 1986), but it is unclear whether this relates to its limited capacitance or limited clearance. To assess its capacitance, a closed loop of duodenum was maintained in Krebs solution and filled with 0.2, 0.4 and 0.8 ml while its pressure and configuration were recorded on videotape. Pressure rose sharply on filling, and then fell to a lower baseline as duodenal diameter increased gradually. Propagating ring contractions developed subsequently and narrowed the di~_~eter intermittently (as recorded by scan line), 0 Ca-- Krebs (or I0- M TTX) abolished the initial pressure peak, the ring contractions and increased the duodenal diameter (pressure peak down to 13 • 1 mmHg from 55 • 3 mmHg, diameter up from 3.6 • 0.4 mm to 5.3 • 0.2 mm). To assess its clearance, the duodenum was perfused at 0.2 ml/min, with outflow resistance set at i0 cm H O. 0rthograde perfusion produced ring contractions t~at propagated over the duodenum at 5 s intervals, lasted up to 2 s, and generated waves up 'to 20 mmHg. Retrosrade perfusion generated "segmental" contractions of the proximal duodenum that occurred at 20 s intervals, generated pressures of up to 50 mmHg, and lasted up to 5 s. Duodenal clearance occurred with propagating contractions on orthograde and with the "segmental" contractions on retrograde perfusion. The threshold volume and pressure, and the t/2 for duodenal clearance were high 9_I with retrograde than with orthograde perfusion. 0 Ca-- and TTX prolonged the t/2 for duodenal clearance and abolished the difference between orthograde and retrograde perfusion, We conclude that i) the isolated duodenum adjusts its diameter to volume (i.e. it accommodates), and its contraction patterns to the mechanical stimulus (i.e. it generates more than one intrinsic reflex) and that 2) a decrease in its mechanical activity may increase the resistance generated by the duodenum despite an increase in duodenal diameter; this is because the simultaneous decrease of duodenal clearance limits duodenal capacitance.

De Angel• Milan, Italy. Activation of muscarinic receptors is required for the regular occurrence of MMCs in the dog (Am. J. Physiol. 1979, 237:E451; Can. J~ Physiol. Pharmacol. 1982, 60:794). Because subtypes of this receptor are known to exist in the gut (Gastroenterology 1978, 74:598), we became interested in investigating the role played by the M subtype in the regulation of the MMC pattern. We therefore studied the effect of atropine (A) and pirenzepine (P), a M selective I antagonist, on the MMC pattern in 7 dogs chronically implanted with electrodes along the small bowel. MMC period and migration velocity were measured in the upper jejunum. A (I0-30 ug/kg i.v.) significantly p r o l o n g e d t h e MMC period from 87.5 to 152.0 and from 71.7 to 170.8 min respectively (n=6), and blocked migration of the ongoing complex. Migration velocity of the MMC following administration was significantly decreased (from 6.5 to 4 and from 5.8 to 4 cm/min, respectively). Lower doses of A were without effect. In contrast P (10-30 ug/kg i.v.) produced premature onset of the MMC following administration, significantly reducing MMC period from 106.0 to 67.7 and from 96.8 to 73.7 min, respectively (n=7). Similarly to A, P reduced migration velocity of the following MMO (from 7.3 to 4.9 and from B.2 to 4.7 em/min). The results confirm the relevance of mueearinic mediation in the control of the MMC pattern. They suggest that onset and migration are regulated by separate muscat• mechanisms, as demonstrated by the differential effect of A and P on these parameters. It appears that P removes a muscarinic brake, mediated by the M subtype, regulating cyclic activation of interdigestive mo~ility.

0-

Postoperative Week 1 1-2

2

+

Pacesetter potential frequency(eycIes/min)

3.1 Yo.2

3.0" 0.1

3.0--57.1

Signal amplitude (mierovolts)

228 + 52

267 + 62

281 + 71

0.35 + ,04 0.39 + .04 0.39 + .05 Conduction veloccity (cm per second) Pacesetter potentials observed in the fundus followed an organized pattern of activity and this was simultaneously seen in the body and antrum of the stomach. In addition, during 4 recordings in'3 patients action potentials were noted in the fundic area in a frequency of up to 15% of associated pacesetter potentials. Action potentials were not present in the initial postoperative week. They were most common in the period of time directly following ingestion of a liquid meal. These data demonstrate evidence for the presence of myoelectric activity in the fundus of the human stomach,

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Digestive Diseases and Sciences, Vol. 32, No. 8 (August 198~

ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY DOES CISAPRII)E ENHANCE GASTROINTESTINAL MOTILITY VIA PREJUNCTIONAL MUSCARINIC (MI)-RECEPTOR INTERACTIONS? J.A.J. Schuurkes, P.J.E. Van Bergen and J.M. Van Nueten. Janssen Pharmaceutiea, B-2340 Beerse, Belgium. Cisapride stimulates gastrointestinal motility most likely by enhancing the release of aeetyleholine from myenterie nerve endings. Such effect could be mediated by blockade of presynaptie musearinic (Ml)-receptors. Our aim was to determine whether nisapride could antagonize the effects of a Ml-agonist , McN-A-343 or mimiek the effects of a Ml-antagonist , pirenzepine on the guinea-pig ileum. Longitudinal Segments were suspended in krebs solution (95 % 02, 5 % C02, 37.5 ~ C) for isometric tension recording (preload 1 gram) during electrical transmural stimulation (0.i Hz, I msec, sub - or supra~aximal current). Results are given as means ! sem,n ~ 6. MeN-A343 (2 x 10 -6 M) reduced the contractile response to supramaximal stimulatio n by 41 • 2 %, but had no effect on the contractions induced by exogenous acetylcholine. Pirenzepine (9 x 10 -8 M) (but not atropine) reversed the McN-A-343-induced inhibition (ED50 = 1.6 x 10 -8 M) at concentrations • 50 x below the concentrations needed to reduce the responses to exogenous aeetylcholine (ED50 = 8.5 x 10 -7 M), Cisaprlde hardly affected the McN-A343induced inhibition. When a reduction of the contractile response (with 44.0 • 1.5 %) was brought about by reduction of the electrical current to submaximal level, plrenzepine did not reverse this diminution. In contrast, cisapride (3.4 x 10 -7 M) enhanced the reduced response, even in the presence of pirenzepine. Moreover, the dose response curve of the inhibition by NoN-A-343 of the contractile response to snpramaximal stimulation was shifted to the right by pretreatment wit~ pirenzepine, but not with eisapride. In conclusion: the effects of MeN-A-343 and pirenzepine on the electrically stimulated gulnea-pig ileum are compatible with an interaction on presynaptic musearinie(Ml)-receptots. Cisaprlde enhances the twitch amplitude via mechanisms independent of such Ml-reeeptor interactions.

THE MOTILITY EFFECTS OF IGE-~DIATED INTESTINAL ANAPHYLAXIS IN THE RAT. R.B. Scott, S.C. Diamant and D.G. Gall. Department of Pediatrics and GI Research Group, University of Calgary, Calgary, Alberta, T2N 4NI, Canada. The effects of IgE-mediated mucosal reactions on intestinal motility were examined in an animal model of intestinal anaphylaxis. Methods: Hooded-Lister rats (i00150 gm) were sensitized (S) by intraperitoneal injection of I0 pg egg albumin (Ag) and compared to sham-sensitized controls (C). Seven days later animals were surgically prepared with 3 pairs of bipolar jejunal electrodes spaced 2.5 cm apart, and a jejunostomy tube for both motility recording and Ag administration. Animals were Studied on day 14, after an 18 hr fast. Intestinal myoelectric and motor activity were measured a) in fasted animals for three cycles of the migrating myoelectric complex before and then after intraluminal administration of either i0 mg egg albumin (Ag) in 0.5 ml saline, or placebo (P) challenge with 0.5 ml saline, and b) in fed animals in a 15 minute period before and after Ag or P challenge. Results: Specific IgE serum titres were > 1:64 in S animals while C animals showed no response. None of the control animals challenged with P or Ag, and none of the S animals challenged with P stooled after challenge; but all the S animals challenged with Ag (fasting or fed) developed diarrhea (p<0.00l). Placebo or Ag challe~ge of C and S animals during fasting or after feeding caused no change in slow wave frequency, spike activity, or motility index. However, in S animals challenged with Ag the fasting motility pattern was disrupted, the migrating motor complex was abolished (p=0.O02) and the frequency of chorally propagating clustered contractions was increased (p<0.01). In fed S animals challenged with Ag there was a greater intensity of the aborally propagating clustered contractions (p<0.05). Conclusion: IgE-mediated mucosal reactions to food protein disrupt fasting intestinal motility and during fasting or after feeding produce a specific pattern of myoeleetric and motor activity associated with diarrhea.

BILE PARTITION AND BILIARY PRESSURE DYNAMICS DURING FASTING AND AFTER FEEDING. R.B. Scott and S.C. Diamant. Department of Pediatrics and GI Research Group, University of Calgary, Calgary, Alberta, T2N 4NI, Canada. Duodenal bile acid output, gallbladder (GB) filling/ emptying; and sphincter of Odd• (SO), common duct and GB pressures were evaluated in 6 dogs in the fasting and postprandial periods. Gallbladder filling/emptying and duodenal delivery of [14C] taurocholic acid (TCA) were measured dur~tg exogenous IV TCA infusion with SO intact using duodenal markerperfusion to measure output, or with SO eliminated by canulating the common duct and directly measuring output. During fasting, a) partial GB emptying and maximum duodenal delivery occurred at 60-90% of each cycle of the migrating motor complex (MMC) whether SO was intact or canulated, b) integrated average SO pressure fell from a high of 14.0 • 9.8 at 95% to a low of 8.7 • 6.5 mmHg at 65% of the MMC cycle (p<0.05), concurrent with a decrease in frequency of SO contractions from 10.6 • 5.9 to 5.7 • 4.4 epm (p
EFFECT OF A NOVEL PROSTACYCLIN ANALOG ON GASTRIC EMPTYING AND SECRETION IN PRIMATES. T. Sbea-Donohue, A. Kandasamy and A. Dubois. Digestive Diseases Div., Dept. of Medicine, Uniformed Services University, Bethesda, MD 20814 U.S.A. Prostaglandins, especially PGE2, have been considered as potential anti-ulcer agents because of their ability to inhibit acid secretion in addition to "cytoprotective" properties. However, therapeutic doses of stable analogs of PGE 2 have undesireable side effects such as diarrhea, due in part to their stimulation of smooth muscle contractility. In contrast to PGE2, prostaeyclin suppresses gastric motility. Therefore, we examined the effects of the stable prostacyclin analog, U68,215, on gastric function in primates. In 4 conscious rhesus monkeys, a marker (Tc-99m-DTPA or phenol red) dilution technique was used to determine concurrently+ gastric fractional emptying rate (FER) and hydrogen ion ( H ) output before and after histalog (HIS, img/kg suhcutanously), HIS plus U68,215 (50 ~g/kg, intragastrically), an 80 ml beetspeptone meal (BAC, 20%, intragastrically, pH 7.4) or BAC p~us u6g,215. U68,215 did not alter fasting FER (table) or H output. HIS significantly enhanced fasting FER by 71% and this effect was decreased by U68,215. FER was significantly enhanced 50% by the BAC meal and this rise was significantly inhibited by U68,215. In addition, U68,215 significantly suppressed HIS-stimulated acid secretion by 63% (18• vs 7• ~Eq/~in), In contrast, U68,215 did not alter the BAC-indueed rise in acid secretion. U68,215 HIS HIS+U68 BAC BAC+U68 1.33 6.63* 2.68 3,82* 1.44 + • • • • • • * p<0.05 vs CONT; + p<0.05 vs BAC These results demonstrate that U68,215 i s a potent inhibitor of both HIS- and BAC-stimulated emptying but is less effective in the reduction of acid secretion. Prostacyclin on the other hand produces an equal suppression of both acid and emptying. These data suggest the a combination of a low dose of an analog of PGE 2 and U68,215 would produce an effective antisedretory compound without the unwanted action on gastric motility. FER

CONT 1.89

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY THE INTRAGASTRIC CORRELATE OF THE SURFACE GASTROGRAM - AN EXPANDED CONCEPT. D.R.SINAR, J.M.JOYCE, Dept s of Medicine, Physics, East Carolina School of Medicine, Greenville, NO. Slow wave frequency is similar from surface eiectrodes and singl 9 intragastric (IG) electrodes, but the IG area within the stomach which correlates with the surface signal has not been defined. The study purpose is to determine similarities in wave forms andfrequency variations among multiple IG signa!s and to determine the approximate size of the IG unit corresponding with the surface gastrogram. Eight cynomolgus monkeys studied after an overnight fast, were lightly sedated and restedquietly during the 120 man study. Seven multipolar mucosal electrodes were endoscopiealiy anchored in two parallel rows along the greater curvature of the stomach and skin electrodes were placed on the abdominal wall to produce eight electrode pairs. Anilog data were processed using Fast Fourier Transforms to produce frequency and power fog each 3.2 man period from egch electrode. Coherence (C) was calculated for each combination of surface and IG electrode pairs. High C (1.0) between two electrodes indicates aN identical wave form. Results: Mean C between surface electrode sets was 0.69 ! 0.08, between IG electrode sets was0.60 + 0.02 and between surface and IG sets was 0 . B g ! 0.03. By subgrouPing electrode pairs, a distinct high coherence zone (range 0.82-0.85) was identified in all animals between surfaee/IG pairs as the maximum C possible with there electrode positions. A frequency gradient was evident from IG electrodes for each animal with the lowest frequency along the lesser curvature (2.55 ~ 0.08 cpm),and the highest frequency along the greater curvature (2.74 ~ 0.ii cpm) in the area of the pacemaker. The closer aft electrode pair was to the paqem@ker,the higher the frequency. Conclusions: i) In the monkey, surface electrodes measure a Wave form oorrespondingwith a distinct intragastric unit of smooth muscle activity. 2) IG electrode pairs have the highest coherence in the area of the gastric pacemaker and lower coherence outside the area of the pacemaker. 3) A mapping study using a larger number of electrode pair s can defin@ the location/size of the gastric pacemaker in each animal and an IG unit of correlation with the surface gastrogram.

INTESTINAL MOTILITY DURING INFECTION WITH HIGH AND TRACE SHIGA-LIKE TOXIN PRODUCING STRAINS OF ENTEROPATHOGENIC ESCHEEICHIA COLI IN EABBITS. R Sjogren, I Pintado, D Sharpnack, D Fritz, E Boedeker. Divisions of Medicine and Pathology, Walter Reed Army Inst of Rsch, Wash, DC 20307. Enteropathogenic B.coli strain RDEC-I produces increased intestinal motility in infected rabbits. This organism makes trace amounts of a shiga-like toxin (SLT). To stu'dy the role of SLT in diarrheal infection, we infected rabbits with RDEC-I or an isogenic strain, RDEC-N19A, that produces large amounts of SLT. We compared clinical, histologic and motor responses in 5 uninfected, 6 RDEC-I infected and 7 RDEC-H19A infected animals. Weight, rectal culture (0 to 3+ confluent growth) and presence of diarrhe~ were monitored. After 7 da of infection, in vivo ileal loops were prepared with serosal electrodes. Myoelectric data was computer analyzed for SW, SB, action potential complexes (SB >2.5 sec, APC) and repetitive bursts of action potentials ~RBAP). Both strains colonized ileum and proximal colon and demonstrated similar enteroadherence 5y electron microscopy. Light microscopic changes were minimal with NDEC-I. In contrast RDEC-HI9A produced substantial enterocyte necrosis, transmural edema, heterophilic infiltration and endothelial swelling. Weight 10ss , rectal culture and incidence of diarrhea were greater in RDEC-H19A infected animals. Increases in spiking occurred in both groups, but were markedly greater with RDEC-H19A. Uninfected RDEC-I RDEC-H19A Rectal Cultures (0-3+) 0 2.8 2.9 Diarrhea 0 2/6 6/7 Weight Gain (g/d) ~7.4 5.3 * - 9.5 * % S W with Spikes 1.3 6~3 * 19.1 ? Spike Bursts (#/hr) 27.4 65.0 * 192.4 t APC (#/hr) 0.1 4.6 ~ 10.3 % RBAP (#/hr) 1.0 5.5 ~ 18.9 9 p<0.05 compared to uninfected; T p<0.05 compared to RDEC-I We conclude that infection with a high SLT producing organism results in a more severe diarrheal illness, a transmural necroinflammatory response and a significant increase in ileal my6electric activity. TheSe data suggest that SLT is an important factor in the intestinal motor response to certain E.coli enteric infections.

I~qE-MODULATION OF GASTROINTESTINAL MOTILITY J;W.Sissons, C.Duvaux*. L.M.J.Heppell, H.E.Pedersen and F-.R.BelI. AFRC Institute of Grassland and Animal Production, Shinfield, Reading, Berkshi
CENTRAL AND PERIPHERAL EFFECT OF NEUROPEPTIDE Y ON INTESTINAL MOTILITY. C.A. Sninsky, S.P. Kalra, D.F. Lynch, and M.G. Dube, VA Med Ctr, and Dept of Med and Ob-Gyn, University of Florida, Gainesville, FL 32602 U.S.A. Neuropeptide Y (NPY) is localized predominantly in brain and coexists with adrenergic neurons periphe~ally. This c o - l o c a l i z a t i o n appears important because certain effects of NPY are mediated by ~-2 adrenergic receptors. Interestingly, i n t r a v e n t r i c u l a r (icy) NPY has been Shown to stimulate feeding behavior (Endocrinology 1985, 117:2435). Because there are d i s t i n c t myoelectric patterns Of the small intestine in the fasted and fed state, we postulated that NPY would a i t e r intestinal m o t i l i t y . Four groups of animals were prepared with either icv or jugular (iv) catheters for central o r peripheral i n j e c t i o n , respectively. NpY was injected as a 2 ug bolus or as a 5 ug/h infusion for 3 h. Each rat acted as i t s own control. Injections were begun at the same time in phase I I of the MMC. Intestinal myoelectric a c t i v i t y was monitored by 4 indwelling electrodes in unanesthetized Wistar rats. Myoelectric records were analyzed for time to a c t i v i t y f r o n t (AF) on lead #2 a f t e r i n j e c t i o n ; AF interval on electrod e i and 4; and propagation velocity. Mean _+ SEM in minutes. AF Interval AF Interval AF Onset #1 AF Pro Vel #4 Saline "16.18e2.44 11.87-+1.91 2.21-+0.24 13.45-+0.43 NPY 2~g icv 29.73-+693+ 11.73+0.63 2.45-+0.33 17.64-+1,41 5~g/h 16.76_+2.39 15.11-+1.40 2.73-+0.84 27.03+5.29t NPY 21ag/iv 33.79_+3.56t 14.61+1.36 2.67-+0.20 18.0!+1.28 Pro Vel cm/min; tp
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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY COMPARISON OF A PERFUSED SIDE HOLE MOTILITY CATHETER AND MICROSTRAIN GAUGE CATHETER FOR TIMING OF EVENTS IN THE PHARYNGOESOPHAGEAL SEGMENT. J. Stancher~ J. Hamilton, J. Robbins Depts of Mad. and Neuroi., Univ. of Wisconsin, Madison, WI 53792 U.S.A. Because the changes in pressure that occur in the upper esophageal sphincter(UES) and pharynx are rapid, commonly available perfused systems may not be accurate enough to use in investigationsef the pharyngoesophageal area. To investigate the accuracy of timing with a perfused system, we have compared the perfused cathete§ system to a catheter with microstrain gauges (Millar, Houston Tx). For this report, we have analyzed recording from perfused ports or microstrain gauges placed within the UES and 4 cm above. The perfusion rate of the side-hole catheter was 0.6 cc/min, Seven normal subjects were studied. Each subject swallowed 5 ec of barium paste x 4, the initial catheter was removed and the alternate placed and the subject again was studied during 4 paste swallows. The video image, a real time clock, and a simultaneous video image of the chart recorder were all recorded on the same video tape fo~ subsequent frame by frame analysis. We found that the duration of sphincter relaxation was significantly shorter for the strain gauge recording than with the side-hole (0.37 s e c v s 0.59 sac; p<0.001). When the strain gauge add side-hole recordings were compared to fluoroscopic events, several differences were found: IP-BC MR-BC ER-BC Strain Gauge -0.08* -0.09 0.51 Side hole 0.002 0.07 0.70 P value (paired T test) <0.05 <0.05 <0.QI (IP=initiation of pha#yngeal contraction inproximal lead, BC=bolus present at ericopharynx, MR=point of maximal sphincter relaxation, EE=point at which sphincter returns to preswallow baseline pressure. *Time in seconds.) The significant differences in the timing of pharyngeal events between the micros/rain gauge and the perfused system indicate that perfused catheters may not accurately reflect swallowing events. In the study of oropharyngeal dysphagia, this critical difference would indicate that the microstrain gauge system would be preferred.

M E C H A N I S M OF INHIBITORY ACTION OF GALANIN ON MYENTERIC NEURONES OF G U I N E A - P I G SMALL INTESTINE. K , T ~ J.M. Palmg r~ M~ ~qhgmann, C_L.Winkelmann and J. D. Wood. The Ohio State University, Columbus, OH 43210, U.S.A. The long aboral projections of galanin-immunoreactive neurones in the ENS suggest a physiological role for this peptide in control of intestinal motility. Our aim was to investigate the effects of galanin on the electrical behavior of enteric ganglion cells and tO elucidate the mechanism of its interaction w i t h other putative m e s s e n gers. Conventional intracellular methods with 3M KCl-filled microelectrodes were used to record electrical actSvity in AH /type 2 m y e n t e r i c neurones from guinea-pig small intestine ~ vitro. Galanin, ACH,histamine, forskolin, substance P, v a s o a c t i v e i n t e s t i n a l peptide(VlP) and ealcitoningene-related peptide(CGRP) were applied by addition to the superfusion solution or by pressure ejection from micropipettes. Application of gelatin (0.1nM-20~M) to neurones mimicked slow inhibitory postsynaptic potentials (IPSPs) which consisted of m e m b r a n e hyperpolarization, decreased input resistance and decreased excitability. Membrane hyperpolarization was reversed near the K+ equilib r i u m potential suggesting opening of K+ channels as the ionic m e c h a n i s m of galanin's inhibitory action. G e l a t i n exerted its effects in the presence o f TTX (0.5~M) indic ating a direct effect on neurones. Galanin also blocked fast and slow excitatory poetsynaptic potential~ (EPSPs) evoked by focal extraaellular stimulation of interganglionic fiber tracts. Galanin sgppressed excitatory responses evoked by applidation of histamine, VIP, ACH, forskelin, substance P and CGRP. I n h i b i t i o n of exhitatory responses to these substances by galenin differed from that of adenosine which inhibits receptor-coupled increase of cyclic AMP and does not offset excitatory responses to substance P 4nd CGRP. The results suggest that galanin is a potent inhibitory peptide in the ENS and m o d u l a t e s excitatory responses to other putative messengers. Galanin m a y not only suppress receptor-coupled cyclic A M P p r o d u c t i o n hut also m a y modnlate changes induced in intraeellular Ca2+ homeostasis. (Supported by N I H DK26742 to J.D.W., DK07308 to JoM,P. and Tokai Univ. r e s e a r c h grant to K.T.)

STUDIES ON THE GENESIS OF COLIC, M.A. Stokes, K;3I Moriarty and 8,N. Catchpole. Depts. of Surgery and Medicine~ U n i v e r s i t i e s of Manchester and Western A u s t r a l i a , Hope Hospital~ Salford M6 8HD. 'Colic' is a frequently used clinical term which has defied precise definition. This study sought to clarify the motor events in the gut associated with simulated 'colic' in order to assist its definition. A method was developed in man of inducing 'colic' locally and sensing associated p r e s s u r e changes. 5-1umen tube systems, e a c h carrying a s o f t balloon, were u s e d . One lumen i n f l a t e d t h e b a l l o o n w h i l e 2 s e n s e d pressure proximally and 2 distally to it by suitable ports. Thus the p o r t s a s s e s s e d c o n t r a c t i o n s o v e r 24 o r 32cms o f g u t . Sensing channels were water perfused (0.2ml/min) and recorded v i a t r a n s d u c e r s on a r e c t i l i n e a r polygraph. The method of l e o ! i t ' induction f i n a l l y adopted was balloon inflation short of causing discomfort followed by saline bolus injection via the port immediately orad to it. Studies w e r e made of the duodenum, jejunum, ileum and various parts of the colon, passing the tube system orally, via enteral stomas or per rectum, without prior patient preparation. Recurring contractions, t h e i r d u r a t i o n , AUC and maximum pressures w e r e noted with pain, with discomfort or without sensation. Findings w e r e : 1) Pain seemed invariably associated with a rise of baseline pressure in a gut segment, at least 6cm and sometimes 32cms long. Pain therefore seemed to be associated with contraction of a segment o f gut. 2) With pain, AUC and contraction wave pressures varied widely between patients. 3) Solitary painless contraction waves of o v e r 250mmHg o c c u r r e d , g) Duration of pain was usually less than one minute. 5) Location of pain~ referable to gut segments, was variable; with increasing severity~ pain spread across the midline. Data suggest a definition of 'colic' as 'a pain usually lasting less than one minute with a slow rise to maxlmum severity and a similar decline'.

POSTPRANDIAL GH~_NGES IN INTESTINAL SLOW WAVE PROPAGATION REFLECT A DECREASE IN CELL COUPLING. D.Terasaka. A. Bortoff and L.F.Sillin. SUNY Health Science Center at Syracuse, Syracuse, NY 13210 U.S.A. It is well known that feeding alters the intestinal spike activity of fasted animals. However, much less is kno~r about the effects of feeding on intestinal slow wave (SW) activity. The purpose of these studies was to determine the effects of feeding on jejunal SW propagation velocity (SWPV) of cats, following a fast. Six female and 2 male cats were instrumented with 6 pairs of bipolar electrodes implanted on the jejunum 4 cm a p a r t Ten days after surgery recordings were begun of spontaneous electrical activity following an 18 hr fast. Control regordings were obtained for i-2 hr, after which each animal was fed a meal consisting of 60 gm of canned oat food. Recordings were continued during ingestion of the meal and for several hrs thereafter. This procedure was repeated at least twice for each Got. Data were plotted as SWPV (cm/sec) as a function of SW frequency (SWF, c/min). Average SWPV at a SWF of 19/min was 2.45• em/sec (mean of means • SD). At I0 min, 1 and 3 hrs postprandially SWPV at 19 c/min dropped to 2.07• 1.46• am d 1.52• cm/see, respectively. The differ ences between the fasting SWPV and that at.l and 3 hrs was significant (p<.05). In addition, the slope of the curve relating SWPV to SWF dropped from a value of -0.167+.123 in the fasting state to postprandial values of -0.085• -0.044• and -0.062• at I0 min, 1 and 3 hrs, respectively. Again the values at 1 and 3 hrs were significantly lower than that in the fasting state (p<.05). The divergence of the slopes at lower SWF's indicates that the postprandial drop in SWPV is due to an increase in resistance to local circuit current flow, probably the result of uncoupling of intestinal smooth muscle cells. The postprandial effect is rapid in onset, beginning within minutes after ingestion of a meal, and long in duration, beginning to return toward fasting levels only after 3 hrs. These results suggest that an uncoupling factor is released during ingestion of a meal and that i~s effect persists for several hours.

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY MORPHINE WITHDRAWAL DIARRHOEA IS ASSOCIATED WITH IRREGULAR SPIKING OF THE SMALL INTESTINE. M. Thollander, P.M. Hellstrem, T.H. Svensson. Department of Pharmacology, Karolinska Institutet, Stockholm, Sweden. Our recent results show that both clonidlne and morphine inhibit the MMC in the rat. This effect was reversed by the respective antagonists, yohimbine and naloxone. Here we report on the MMC pattern in morphine withdrawal. Male conscious rats were implantedwith two bipolar electrodes 5 and 15 cm distal to the pylorus and were allowed to recover for 7-I0 days before experiments. After a 24 h fast the myoelectrical actlvlty of the small intestine was recorded by an EEG preampllfier operating a Grass Polygraph. Chronic morphine treatment during five days with increasing doses up to 50 mg kg -I i.p. produced an increased interval between the activity fronts. In continuous registration during 30 h after withdrawal of morphine the MMC pattern changed into a myoelectrical activity characterlzed by irregular spiking. An acute withdrawal syndrome was induced by naloxone (I mg kg-! i.v.) 24 h after the final morphine administration. Classical morphine abstinence symptoms were observed ineludingwe~dog shakes, teeth chattering, writhing, ptosis and profuse diarrhoea. Simultaneously, an intense irregular spiking activity was recorded in the small intestine (n=6) i After 30-60 min, administration of morphine (15-30 mg kgi.v.) inhibited the intestinal irregular spiking with a reinstatement of the MMC pattern. Naloxone (I mg kg -I i.v.) administered to unpretreated, control rats had no effect on either intestinal myoelectrical activity or behaviour, The present results thus show that intense irregular spiking activity occurs in morphine withdrawal which may represent a mechanism underlying decreased intestinal transit time and diarrhoea observed in the syndrome.

PRIMARY CULTURES OF INTESTINAL MUSCULAIURE~ CORRELATION BETWEEN PRESERVATION OF SPONTANEOUS RHYTHMICITY AND PRESENCE OF INTERSTITIAL CELLS OF'CAJAL. WITH VIDEO, DEMONSTRATIONS, L.Thuneberq and S.Peters. Univ. Copenhagen, AnaL. Dept. C, Psnum Instituttet, DK-2200 Copenhagen N, Denmark. He culture pieces of mechanically isolated musculature from meuse small intestine in Rose chambers equipped with silicone rubber gaskets. To test our working hypothesis, that interstitial cells of Cajal associated with Auerbach's plexus (ICC-AP) ere intestinal pacemaker cells (Adv. Anat. Embryol. Cell Bin1. 1982, 71:l) we search for culture conditions which optimally preserve a spontaneous rhythmicity, while simultaneously allowing the contracting tissue to grow and spread on a surface. Uith 3-4 mm thick gaskets (chamber volume 2-5 ml) carefully dissectpd muscle may preserve a sbrong rhythmicity for many weeks. However, the rhythmic conbraetione are restricted to the original explant, which forms e thick, rounded, pulsating mass. Outgrowing muscle cells either are pulled back or torn, or, iF muscle outgrowths persist, these are quiescent. Under the same eondibions, but with i mm gaskets (chamber volume 0.7 ml) the force of contractions is lower, and bhin, rhythmically contracting muscle outgrowths may form. ~hen ~CC are identified by phase contrast morphology, by methylene blue (MB) uptake, and by uibrastructure after MB staining, we observe hhat spontaneous, rhythmic contractions of muscle cells occur only where ICC are present. The ICC exhibit an extreme plasticity, ~ith rapidly changing cohfigurations of long, thin, branching processes in close contact wibh muscle cells~ moving with these. OFten one or more ICC processes or, most often, a single, strebehed region of a long process exhibits active eonErsctions. 14hen Ehe cultured ICC are selectively stained with MB and il~uminated, rhythmic contractions of tne ~uscls stoo. Uhen ICC-AP nave oeen selectively stained with suoravita] MB before culturing tne tissue, no spontaneous oontractlons develoo in culture, in contrast ~o conbrol tissue From nne same intestlne.

ROLE OF [:CK/GASTRIN RECEPTORS IN FASTED AND FED MOTILITY PATTERN AND PANCREATIC SECRETION. P. Th~r_a J, Leskiewicz and S.J, Kpnturek. Inst. Physiol,, Krak~.~, Poland,

CHARACTERIZATION OF THE EARLY PATHOPHYSIOLOGY OF DIABETIC GASTROPARESIS. J.L. Urbain, J.A. Siegel, M. Buysschaert, S. Pauwels. Louvain School of Medicine, Brussels, Belglum Many of the radionuclide studies have shown that the gastric emptying of solid food is impaired in diabeticorum gascroparesis, The purpose of this study was to better characterize the early pathophysiology of asymptomatic diabetic gastroparesis by quantifying the lag (early) phase and the rate (late phase) of gastric emptying of solid food. Eleven diabetic patients with cardiac autonomlc neuropathy (CAN) and 9 age--matched diabetic patients without CAN (CAN-) were compared to 9 healthy controls (CONT). All patients and CONT were asym~tomatic and no abnormalities were found on barium studies or endoscopy. CAN was based upon measurement of the variation ol heart rate during deep breathing. Gastric emptying of solids and liquids was measured after ingestion of a standardized dual-label meal using Tc-99m-SC scrambled eggs and In-lll-. DTPA in water. Anterior and posterior images were obtained every 20 minutes for two hours and corrected for decay and downscatter. Solid geometric mean data were generated and analyzedusing t~e modified power exponential y=l-[l-exp(-kt)] which permits quantitation of the lag phase (TLAG), the empcying rate (ER), and the half--emptying time (T~). Liquid data were fit using a single exponential function. Results are summarized below (mean• SOLIDS LIQUIDS Group N TLAG ER (I/min) T~ ER T~ CONT 9 68• 0.024• 89t28 0,019• 49• CAN9 56• 0.020• w177 0.019• 44• CAN II 86• 0.015• 119• 0.014• 52• *p < 0,0025 Gastric emptying of solids was significantly delayed in diabetics with autonomic neuropathy, which was mainly due =o a larger TLAG. We conclude that prolongation of the lag phase appears to be the earliest abnormality of gastric emptying of solid food in an asym~tomatic diabetic patient with autonomic neuropathy. This is suggestive of an impairment of the neurovegetative control of antral motility.

Recent description of highly specific and potent CCKreceptor antagonists permits the evaluation of the role of CCK and gsstrin in the fasted and fed motility pattern of the small intestine and the pancreatic Secretion. In this study we used for this purpose one of the most

potent of all as yet described C:CK antagonist (0R-1409) (Rotta Labs Milan) which was infused i.v. in various doses in dogs with monopolar electrodes'implanted along the small bowel for recording the myoelectric activity and pancreatic ~istula for measuring p~ncreatic secretion. In fasted dogs, CR-1409 infused i.v. failed to effect the motility pattern and the fluctuations in basal pancreatic secretion related to migrating myoelettric complex (MMC). CCK8 (100 pmol/kg-h), gastrbn (I00 pmol/kg-h) or bethanechol (0.5 ~mol/kg-h) infused i.v.interrupted the M~C and induced fed-like motility pattern accompanied by a m a r k e d increase in pancreatic protein secretion reaching about 62%, 27% and 38% of the CCK maximum. CR-1409 at lower dose (0.5-1.0 ~mol/kgZh) inhibited dose-dependently the fed-like moti?ity pattern end reduced dose-dependently pancreatic protein secretion induced by CCK8 but not by gastrin or bethanechol. At higher doses of CR-1409 (2.0-8.0 ~mol/kg-h), phase III of MMC was restored mostly in the upper portion of the small 6owel and psncreatip protein secretion was suppressed in tests with CCK8 and gastrin but not bethanechol. CR-1409 at h i g h e r d o s e s reduced by about 25% the intestinal spike actiuity induced by meat feeding and inhibited by about 30% the postprandial pancreatic protein secretion. This study demonstrates that CCK and gastrin do not play any important role in fasted small bowel mortify and pancreatic secretion but contribute, in part, to the conversion of fasted to fe d motility pattern and in the postprandial stimulation of pancreatic secretion.

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY AUTOTRANSPLANTATION OF THE ENTIRE CANINE STOMACH: EFFECTS ON MOTILITY. J.A. Van Lier Ribbink and M.G. Sarr. Mayo Medical School, Rochester, MN 55905 U.S.A. The mechanisms c o n t r o l l i n g gastric and small bowel motil i t y are not well understood. AIM: To determine the effects of complete neural isolation of the stomach (autotransplantation) on c o n t r a c t i l e and myoelectrie a c t i v i t y of the stomach and small bowel. PREPARATION: In 4 dogs, all connections to the entire stomach (nerves, vessels, lymphatics, etc.) were transected and ligated except for the isolated l e f t gastric and splenic vessels which were meticulously stripped under optical magnification of investing adventit i a . Distal esophageal and proximal duodenal transection completed the "autotransplantation"; the walls of the l e f t gastric and splenic vessels were the only persisting o r i g i nal connections to the stomach. Enteric continuity was restored, and serosal electodes and manometric catheters were implanted on the autotransplanted stomach and small bowel. DESIGN: After 3 wk, m o t i l i t y was studied on 4 or more occasions during fasting and after feeding 200 g l i v e r , and compared to control dogs. RESULTS: During fasting, a cyclic motor pattern persisted in the autotransplanted stomach and was coordinated with the migrating motor complex (MMC) in the small bowel. The period of this gastric MMC-like a c t i v i t y (116+20 min; ~SD) was no d i f f e r e n t than controls (95+8 mint P=0.14), the duration of phase I l l - l i k e a c t i v i t y (17~15 min, ~+SD) was similar to controls (18+2 min), but the pattern o~ contractions was abnormal. Ta~hygastria accounted for 33% of the antral myoelectric a c t i v i t y compared to < 1% in controls (P
ELECTRICAL PROPERTIES AND SYNAPTIC BEI!AVIOR OF MYENTERIC NEURONS IN GUINEA-PIG DISTAL COLON. P.R. Wade and J.D. Wood. Ohio State University, Columbus, OH 43210 U.S.A. Intracellular recording methods were used in vitro to characterize the electrophysiological properties of neurons in myenterie ganglia of guinea-pig colon. Segments of colon were removed i0 to 20cm distal to the hypogastric flexure. LM-myenteric plexus preparations and methods like those used in similar studies of small bowel myenteric neurons were employed. Six cell types were identified based on active electrical properties. Type 1 neurons (11% of total) discharged action potentials (APs) throughout outward current pulses and fired APs by anodal-break excitation. APs of Type i neurons were sensitive to 0.i~M TTX. Type 2 neurons (24%) discharged single spikes at the onset of outward current pulses and half of these ceils displayed anodal-break excitation. APs of Type 2 neurons were TTXinsensitive and were followed by a slow hyperpolarizing after-potential (AH). Type 3 neurons (7%) did not generate APs but exhibited fast synaptic or electrotonie potentials. Type 4 neurons (41%) discharged single spikes at the onset of outward current pulses but did not display anodal-break excitation. APs of Type 4 neurons were TTX-sensitive and were not followed by an AH. Type 5 neurons (6%)exhibited spontaneous spike activity and fired single APs or erratic bursts of APs. Type 6 cells (ii%) did not fire APs, lacked fast synaptie potentials and presumably were glial cells. Fast excitatory post-synaptie potentials (EPSPs) occurred spontaneously or were evoked by single electrical shocks to interganglionic connectives in all types of colonic neurons. Fast EPSPs were reversibly blocked by TTX, reduced extracellular Ca++ and elevated Mg~ , or hexamethonium, Repetltive stimulation of interganglionic connectives evoked slowly-developing, sustained excitation in Type 2, 3 and 4 colonic neurons or slow hyperpolarizing potentials in Type 2 and 3 neurons. Our results suggested differences between small and large bowel myenteric ganglia. One difference was the electrical behavior of Type 4 neurons~ The other was the abundant spontaneous fast synaptic input observed in most colonic neurons. [Supported by NIH DK37238 and NRSA DK07974].

IMMUNOMODULATION OF GUT MOTILITY: INVOLVEMENT OF CONNECTIVE TISSUE MAST CELLS IN ANTIGEN-INDUCED CONTRACTION OF SMOOTH MUSCLE. D.Vermillion. R.Scicchitano= P_=Ernst and S.M.Collins. Intestinal Diseases Research Unit, McMaster University,Hamilton,Ontario,Canada LSN 3Z5. Antigen challenge produces motility changes in the sensitized gut. However, mechanisms underlying these changes are poorly understood. In the present study, we have investigated the pharmacology and cellular basis for antigen-induced changes in jejunal motility in the rat, sensitized by prior infection with the enteric parasite T richinella spiralis. We measured isometric contraction of jejunal longitudinal muscle strips from naive rats or from rats that had recovered from a primary infection with T.spiralis 32-85 days previously. Antigen from T,spiralis contracted muscle from infected rats hut not that of naive controls. Antigen-induced contraction was not altered by tetrodotoxin (l~g/ml) or atropine (InM). but was inhibited by the non-selective mast cell stabilizer doxantrazole. Histological examination revealed a significant increase in mast cell number in muscle layers of infected rats compared to control. These cells stained positively with safranin but not with alcian blue or rat mucosal mast cell protease II, indicating that they belong to the connective tissue (GT) subclass of intestinal mast cells. This classification was supported further by the ability of the selective CT mast cell degranulating agent 4880 to mimick antigen-induced contraction in this preparation, and by the ability of disodium chromoglycate to partially inhibit contraction induced by T.spiralis antigen. We next examined the mediators involved in this response. Antigen-induced contraction was not inhibited by antagonists to histamine (Hi), but was inhibited by the 5 HT antagonists ketanserin or cyproheptidine. These results indicate th@t antigen-induced contrac~ tion of smooth muscle from the sensitized gut is mediated by the release of 5-NT, b u t n o t histamine, from connective tissue mast cells that proliferate into the muscle layers of the gut following initial exposure to the sensitizing antigen. (Supported by M.R.C. Canada).

PACEMAKER ACTIVITY RECORDED FROM CIRCULAR MUSCLE JUST PROXIMAL TO THE LOWER ESOPHAGEAL SPHINCTER OF DOGS. P.D.Walton and J.D.Huizinga. I.D.R.U., McMaster University, Hamilton, Ontario, Canada L8N 3Z5. Cyclic changes in LES pressure have been ~bserved by others~ in v i v o during the MMC. Our aim was to investigate whether intrinsic properties of circular muscle (CM) of the LES were responsible for its ability to contract phasically. Electrical activity and response to stimulation of intrinsic nerves were studied with the sucrose gap technique in 2 preparations from 2 areas. Zone A: CM taken 3-6 mm proximal to the squamocolumnar border (n=18); Zone B: CM taken distal to this border (n=20). CM in Zone A generated spontaneous electrical slow wave activity with superimposed spikes associated with phasic contractions, which were not eliminated by TTX (5xI0-7M) nor atropine (10-7M). Zone A tissue did not develop active tension. The slow wave frequency ranged from 2.0 6.0 cpm, with a mean amplitude of 3.0• mY, a duration of 3,9~0.2s, and a spike frequency of 1.6• Spontaneous cyclic activity was seen in 18 out of 18 dogs. Nerve stimulation revealed the occurrence of ejp's (cholinergic excitation), ijp's (noneholinergic, non-adrenergic inhibition) and off excitation (partly cholinergie), CM in Zone B invariably developed active tone without changes in electrical activity. No spontaneous activity was observed. Nerve stimulation revealed dominant presence of inhibitory nonadrsnergic nerves. Zone B tissue could produce a similar slow wave-spike activity associated with phasic contractions as Zone A tissue: it occurred after p o t a s s i ~ conductance blockade with 9-amino acridine. Conclusions: CM proximal to the LES exhibits spontaneous electrical activity which could serve as pacemaker activity for the LES. This tissue has rich innervation of intrinsic cholinergie neurons. The body of the LES, mainly innervated by inhibitory neurons, is normally electrically quiescent hut has the capability to produce the same electrical activity as produced by the pacemaker area, providing a basis for phasic contractile activity in the LES.

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ABSTRACTS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON GASTROINTESTINAL MOTILITY L-GLUTAMATE (L-GLU) STIMULATES CHOLINERGIC TRANSMISSION 1N THE MYENTERIC PLEXUS: EVIDENCE FOR RELEASE OF L-GLU AND RECEPTOR SUBTYPE CHARACTERIZATION. J. Wiley~ Y. Lu and C. Owyanq. Dept. of Internal Medicine, The University of Michigan, Ann Arbor, M1 ~8109 U.S.A. Substantial evidence suggests that glutamate (L-GIu) serves as a major excitatory neurotransmitter in the CNS. In this study we explore if L-Glu is released on depolarization of myenteric neurons and investigated whether receptors for L-Glu are present on myenterie neurons. To study the release of L-GIu guinea pig leal longitudinal muscle-myenteric plext~, slices were loaded with H-Glutamine and K -evoked release of H-L-Glu was measured. K+(25-75mM) stimulated dose-dependent release of 3H-L-Glu blocked by a Ca++free medium containing EGTA (I raM) or Mg++ (I2mM). This supports the presence of neurons in the my~nteri# plexus which release L-GIu on depolarization. L-Glu (10-a-10 - M) caused dose dependent ileal muscle contraction. This stimulotory effect was unaffected by hexamethonium, but abolished by atropine and tetrodotoxin indicating L-GIu is acting via postgangllonic neurons. Three types of CNS receptors for L-Glu can be differentiated using N-methyI-D-aspartate (NMDA), kainate (KA) and quisqualate (OO) as agonists. To characterize the receptor subtypes for L-GIp in tj~e myenterie plexus we demonstrated that NMDA (10-~176 but not t
THE MEGACOLONASSOCIATED WITH MYOTONIC DYSTROPHY IS CAUSED BY A NEUROPATHYOF THE MYENTERIC PLEXUS. M.M. Yoshida, S. Krishnamurthy, D. ~attchow, M.D. S c h u f f l e r , Dept. of rledicine, Univ. o f Washington School of Medicine, Seattle, WA, and Dept. of S~rgery, Flinders Medical Center, Adelaide. The e t i o l o g y of GI motor dysfunction in myotonic dystrophy (l|D) is unknown. We describe the pathology of the colon from a male with MD who had a hemicolectomy because of a megacolon. METHODS; Two samples each from the most d i l a t e d and least d i l a t e d areas of the colon were f i x e d f o r : I ) conventional h i s t o l o g y using H & E serial sections; 2) s i l v e r staining of the ~IP using Smith's technique; 3) immunohistochemical staining f o r substance P, enkephalin, neuropeptide Y, and VIP; and 4) transmission electron microscopy (EM). MP neurons were counted in every 8th serial section of 64 consecutive H & E sections and expressed as neuron scores (neurons per section per lOOmm of smooth muscle). Neuron scores were also done on 19 control colons. A r g y r o p h i l i c neurons per 40x f i e l d in three d i f f e r e n t ganglia of each s i l v e r stained slide were quantified and compared with the controls. RESULTS: The colon varied from 7-22 cm in circumference. The mucosa, smooth muscle and connective tissue appeared normal by H & E. The patient had fewer neurons on the H & E serial sections (3.6 in the most dilated area; 12.6 in the least dilated area) than the controls (54.6 + 19.2}. He also had fewer a r g y r o p h i l i c neurons per ganglion (2.3 in the most d i l a t e d area; 4.9 in the least dilated area) than the controls (14 + 2.7). A r g y r o p h i l i c neurons were smaller and had fewe~ processes and an uneven staining q u a l i t y . Many axons appeared fragmented, and increased Schwann cell nuclei were present. There were decreased nerve f i b e r s reactive f o r substance P and enkephalin in the muscularis externa, whereas there Was normal r e a c t i v i t y f o r neuropeptide Y and VlP. EM revealed patchy abnormalities: ballooning of neuron mitochondria, less prominent rough endoplasmic reticulum, fewer neurotubules and neurofilaments, increased coarseness of nuclear chromatin, and fewer axons containing neurot r a n s m i t t e r vesicles. CONCLUSION: The colonic motor dysfunction associated with MD is secondary to a neural abnormality.

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Digestive Diseases and Sciences, Vol. 32, No. 8 (August 1987)