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The effect of somatostatin on pentagastrin-induced gastric secretion was assessed on 6 isolated canine stomachs perfused ex vivo with homologous blood. Hormones were given at a constant rate into the gastric arterial circulation. Somatostatin caused inhibition of the HCl concentration and output and reduced the secretion volume in all stomachs studied. The output but not the concentration of pepsin was also reduced.

Isolated canine stomachs were perfused for 6 h with fluorocarbon emulsion suspended in a simulated physiological solution of electrolytes with glucose added. Gastric mucosa and extramucosal tissues of perfused stomachs were sampled for biochemical analysis of high energy phosphates, glucose and electrolytes. Comparable samples were also taken from normal canine stomachs, dissected under similar surgical conditions as the stomachs used for perfusion. Gastric tissue ATP, ADP and AMP were reduced but CP was increased in the tissues perfused with fluorocarbon as compared with controls. Gastric tissue water content and sodium were increased but potassium was reduced in a stomach so perfused. The biochemical tests performed were considered as viability tests of organs preserved-perfused in fluorocarbon prior to possible transplantation. Significance of the changes observed is discussed in the light of the current knowledge on energy metabolism.

This study was concerned with the effects of prostaglandin-E2 (PGE2) on myoelectrical and mechanical activity of the isolated, homologous perfused canine stomach. A flash injection of 25 mug of PGE2 into the gastric artery led to production of premature control potentials, uncoupling of electrical control activity (ECA) and to a weak mechanical response of short duration. After vagal stimulation of the nerve of Latarjet, or after flash injection of pentagastrin (2.5 mug) or of methacholine (5 mug), similar changes in ECA were observed, but mechanical response corresponding to antral contractions was very pronounced. Prolonged infusion of PGE2 (500 mug/h) induced a marked increase of ECA frequency. A similar effect on ECA frequency was observed during infusion of pentagastrin (32 mug/h). Infusion of PGE2 abolished, but infusion of pentagastrin stimulated, mechanical response. Effects of a flash injection of PGE2 on electrical activity were reduced by hexamethonium and abolished by tetrodotoxin and atropine. The action of the blocking agents on PGE2-induced changes in ECA was similar to the action of these blockers on gastric myoelectrical activity, stimulated vagally or by injection of pentagastrin and methacholine. Infusion of PGE2 induced a marked reduction in gastric peripheral vascular resistance, but no time-correlation between hemodynamic effects of PGE2 and its action of gastric musculature was noted.

Principal glycoproteins and amino acids were determined in porcine gastric juice obtained from totally isolated stomachs perfused extracorporeally with homologous blood. Acid juices collected during prolonged stimulation of stomachs with histamine or pentagastrin, infused into gastric arteries, were used. All samples showed the presence of glactose, glucosamine, galactosamine, fucose, mannose and sulphate. Galactose and glucosamine were found in equimolar amounts and the galactose to galactosamine ratio was, in most samples, 2:1. Compared with human non-stimulated gastric juice studied by others, marked differences were found in the relationship between carbohydrate components and between amino acids. Porcine gastric juice contained much more protein than human gastric juice. Some characteristics of porcine mucinous secretion may be due to conditions of juice collection from the isolated gastric preparation.

Totally isolated whole canine stomachs, perfused ex vivo with homologous blood, were used for recording of myoelectrical and mechanical activity prior to and following the injection

Myoelectrical and mechanical activities were recorded from whole isolated canine stomachs perfused, intravascularly, with fluorocarbon emulsion, oxygenated in vitro. The perfusate was composed of an oxygen carrier, fluorcarbon, emulsified with a surfactant added to a simulated physiological solution. Bipolar electrodes and a strain gauge were used for recordings. Stomachs perfused as above for 5 h displayed normal electrical and mechanical activities. 'Normal' meaning identical with those observed under in vivo conditions or during perfusion with homologous blood. Normal response to electrical stimulation of a vagus nerve branch or to intraarterial injection of methacholine or pentagastrin were also observed. These functions of smooth muscles were not altered when glucose-free or glucose-and phosphate-free perfusate were used. In calcium-free perfusate, electrical and mechanical activities were absent and no responses to stimulants used were recorded. When calcium was added to the perfusate, these functions were restored to normal. Strontium was found to be an adequate substitute for calcium in fluorocarbon perfusate. Gastric secretions were alkaline and contained fluorocarbon emulsion.

Electrical and mechanical activity were recorded from totally isolated whole porcine stomachs perfused with homologous blood. Stagnant, complete ischemia was then produced by closing the gastric artery and vein for various periods of time up to 3 h. After a given period of ischemia, blood was recirculated for 10 min and then pentagastrin was injected into the gastric artery. The vagus nerve was also electrically stimulated at various stages of anoxia and recirculation. After up to 90 min of ischemia, stomachs were able to demonstrate electrical control activity of low frequency after 10 min of blood recirculation. After injection of pentagastrin, electrical control activity rapidly became normal. When ischemia lasted 120 min or longer, recirculation of blood did not induce reappearance of electrical control activity, but pentagastrin injection produced a normal response. After ischemia of 240 min duration or longer, recirculation and pentagastrin had no effect. In previously ischemic stomachs the response to vagal stimulation occurred only in the stomachs responding to pentagastrin.

Electrical and mechanical activity were recorded from the canine stomach, isolated and ex vivo perfused with homologous blood. The action of Bombesin, a natural tetradecapeptide, wa

Isolated, ex vivo perfused, canine stomachs were used for this study. Gastric secretion, myoelectrical activity and mechanical activity were recorded during stimulation of gastric function with pentagastrin or histamine alone or combined with calcium gluconate. Secretagogues and calcium were infused into the gastric arterial circulation. Hypercalcemia induced significant inhibition of pentagastrin, stimulated gastric secretion, but did not affect the secretion stimulated by histamine. Hypercalcemia also induced an increase of frequency of cycles of electrical control activity and a decrease of mechanical activity of the gastric antrum. The effect of hypercalcemia on gastric motor function was similar in the nonstimulated stomach and during the infusion of secretagogues used in this experiment.

The totally isolated canine stomach, perfused with homologous blood, was chloride used for the study of gastric pepsin and HCl. Secretion was stimulated for several hours by intra-arterial infusion of histamine, pentagastrin and bethanechol chloride, given separately or combined. The ratio of outputs of pepsin and HCl (P-O/HCl-O) were calculated. The relationship between paired values of pepsin (mg/30 min) and H+ (mEq/30 min) was analyzed by computer and the linear correlation was calculated between these two values. Bethanechol chloride was found to be a very strong stimulant of pepsin and high (P-O/HCl-O) ratios were found in the presence of cholinergic stimulation applied separately or in combination with the humoral secretagogues used. Bethanechol chloride potentiated the effect of histamine and pentagastrin on pepsin secretion. No such potentiation was observed when histamine was combined with pentagastrin. The relationship between pepsin and acid expressed by (P-O/HCl-O) ratio, was dependent upon the secretagogue used. Linear regression lines satisfactorily characterized the relationship between pepsin and H+ outputs under all conditions of stimulation applied in this experiment.

Totally isolated canine stomachs, perfused with homologous blood, were used for the study of potentiation between pentagastrin and histamine. These stimulants were infused into the gastric arterial system separately, or combined. Gastric secretion and perfusion blood were sampled every 30 min for biochemical analyses Combination of pentagastrin plus histamine gave significantly higher outputs of HCl than could be accounted for on the basis of summation of stimulatory effects. True potentiation, with regard to gastric juice volume and HCl output, occurred when two stimuli were infused simultaneously. Gastric hypersecretion of H+ was associated with increased O2–consumption by the stomach and by the alteration of the physiological relationship between the pH of arterial and venous blood sampled from gastric vessels. It was concluded that the totally isolated canine ex vivo stomach, perfused with homologous blood, is a suitable experimental preparation for the study of potentiation effects between two humoral gastric secretagogues.

The totally isolated canine stomach, perfused with homologous blood, was used to study the inhibitory action of metiamide, a histamine antagonist of the H2-blocking variety. Secretagogues

Totally isolated canine stomachs, perfused with homologous blood, were used for the study of the effect of prostaglandin-E2 (PGE2) on gastric secretion and circulation.

The relationship between oxygen consumption and acid secretion was studied in 28 totally isolated ex vivo canine stomachs, perfused extracorporeally with homologous blood. Two hundred six 30-min samples of gastric juice and blood were collected for biochemical analysis. Paired values of HCl (microequivalents per minute) and O2 consumption (micromoles per minute) were then analyzed by the method of least squares, using a computer. Linear correlation was calculated between these two values. The correlation coefficient was 0.9518 and the slope of the line was 0.512. The ratio of hydrogen ions produced to oxygen molecules consumed was 1.18 ± 0.53. The range of titratable H+ found in this study was from 0 to 833 μequiv/min and the range of O2 consumed was from 18 to 442 μmol/min.

Isolated whole canine stomachs were dehydrated for 4 h and then perfused ex vivo with homologous blood of living supporting dogs. Dehydration was produced by vacuum during which tem

A canine gastroduodenopancreatic block was isolated and perfused extracorporeally with homologous blood. This preparation was used for studying stimulated exocrine secretion of the pancreas. Stimulants were infused intra-arterially. Both vagi were stimulated electrically. Hydrochloric acid or L-phenylalanine were instilled intragastrically. Pancreatic secretion induced by secretin and during HCl instillation was rich in bicarbonate and poor in total protein. Pancreatic secretion obtained during the infusion of normal saline, cholecystokinin, bethanechol chloride or acetylcholine chloride and during instillation of amino acid as well as during electrical stimulation of vagi, contained less bicarbonate and more protein than secretin-induced secretion.

Electrical and mechanical activity was recorded from totally isoltted porcine stomachs perfused with homologous blood, The electrical control activity, response activity, and mechanical reaction to various hormones and drugs stimulationg these activities were recorded. The drugs were injected directly into the gastric artery of the isolated organ. Normal response to cholinergic stimulants and to pentagastrin was observed. The effect of blockers such as atropine, hexamethonium and tetrodotosin on the action of stimulants was also assessed. The results of this study suggest that the release of acetylcholine is involved in the mechanism of action of pentagastrin. They also demonstrate the usefulness of the isolated porcine stomach approach to the study of gastric myoelectrical and mechanical activity.

Totally isolated stomachs, perfused extracorporeally with homologous blood of living oxygenator dogs, were used for the study of gastric secretion. Pentagastrin or histamine were infused into the gastric artery alone or combined with a 30% solution of glucose. Hyperglycemia was associated with significant inhibition of gastric secretion. Volume, output of HCl and concentration of H+ in gastric secretion were decreased. Hyperglycemia induced also a significant increase in osmotic pressure of gastric secretion and gastric blood. Paired values of H+ and osmotic pressure of gastric secretion were analyzed by the method of least squares, using a computer. The regression line was given by the equation: osmotic pressure (mosm/kg)=311.2-0.167 X [H+] mEq/liter.

Canine gastroduodenopancreatic blocks were isolated and perfused ex vivo with oxygenated bloodless fluorocarbon emulsion. Pancreatic and gastric secretions were collected. Exocrine pancreatic secretion was stimulated with secretin infused intra-arterially. This study was undertaken to find out whether or not the pancreas, perfused with fluorocarbon emulsion, preserves its endocrine function. Immunoreactive insulin was determined in the perfusate samples obtained from a venous site in the perfusion circuit. Glucose concentration was also measured in the same samples. Insulin appeared in all experiments within the first ten minutes of persuion of the preparation with fluorocarbon. Insulin was present in all samples collected during 5.5 hours of perfusion. Results of this study suggest that endocrine function of the pancreas was preserved under the conditions of extracorporeal perfusion used.

The myoelectrical and mechanical activities of the totally isolated, canine stomachs were recorded using five sets of bipolar silver-wire electrodes and one strain gauge. Stomachs were perfused extracorporeally with the blood of living supporting dogs which served as oxygenators and dialysers. Each supporting dog had a permanent antral pouch, accessible for the purpose of irrigation. To suppress the release of endogenous gastrin, this antral pouch and the antrum of the ex vivo stomach were irrigated with acid (pH 3). To induce the release of gastrin, one or both antra were irrigated with 0.2-percent acetylcholine or with 1 M glycine. To compare the action of endogenous gastrin with exogenous gastrin-like peptide, pentagastrin was infused into the gastric artery in doses of 4 mug/h and 8 mug/h. Control recordings were done during the acid irrigation. Endogenous gastrin released from antra by acetylcholine or glycine caused identical changes in the recordings as exogenous pentagastrin. There was a marked increase in the frequency of electrical control activity and of gastric contractions recorded as increased mechanical response. The results indicate that the ex vivo stomach can be used for study of the effect of endogenous gastrin musculature activity under the experimental conditions described.

Myoelectrical activity was studied in normothyroid and hypothyroid Labrador dogs in the resting state, following injection of pentagastrin, bethanechol chloride, and after feeding. Hypothyroidism was produced by total thyroidectomy and chronic treatment with thiouracil. Electrodes were surgically implanted over the serosa of the stomach, duodenum, jejunum, and ileum and used for repeated recording of myoelectrical activity of gastrointestinal muscles. A strain gauge was implanted over the gastric antrum and served to record mechanical activity of the stomach. As compared with control dogs, hypothyroid animals showed (a) decreased frequency of electrical control activity of the stomach and jejunum, (b) decreased occurrence of electrical response activity (spike potentials) following stimulation, and (c) decreased mechanical response to the same stimulants, ie, pentagastrin, bethanechol chloride, and food.

Electrical and mechanical activities were recorded from the isolated canine stomach perfused with fluorocarbon emulsion and oxygenated in vitro. This preliminary experiment was undertaken to determine whether or not these activities can be preserved during extracorporeal bloodless perfusion using a perfusate containing only an oxygen carrier, fluorocarbon and a simulated physiologic salt solution of some electrolytes. We found that electrical control activity of stomachs so perfused was identical with that found under in vivo conditions. The electrical and mechanical response of these stomachs to intra-arterially injected methacholine and pentagastrin and to electrical stimulation of the vagus nerve suggested that the function of the muscular and intramural plexus layers of the gastric wall remained normal. It was also observed that the frequency of the cycles of electrical control activity and the amplitude of antral contractions were significantly increased, when pO2 of the circulating perfusate rose. Results of the biochemical studies of the perfusate suggested utilization of some of its components for the metabolic needs of the perfused organ. The gastric secretion was alkaline and contained particles of fluorocarbon emulsion.

Myoelectrical and mechanical activities were recorded from whole isolated canine stomachs perfused, intravascularly, with fluorocarbon emulsion, oxygenated in vitro. The perfusate was composed of an oxygen carrier, fluorcarbon, emulsified with a surfactant added to a simulated physiological solution. Bipolar electrodes and a strain gauge were used for recordings. Stomachs perfused as above for 5 h displayed normal electrical and mechanical activities. 'Normal' meaning identical with those observed under in vivo conditions or during perfusion with homologous blood. Normal response to electrical stimulation of a vagus nerve branch or to intraarterial injection of methacholine or pentagastrin were also observed. These functions of smooth muscles were not altered when glucose-free or glucose-and phosphate-free perfusate were used. In calcium-free perfusate, electrical and mechanical activities were absent and no responses to stimulants used were recorded. When calcium was added to the perfusate, these functions were restored to normal. Strontium was found to be an adequate substitute for calcium in fluorocarbon perfusate. Gastric secretions were alkaline and contained fluorocarbon emulsion.

Totally isolated whole canine stomachs perfused, ex vivo, with homologous blood of living supporting dogs were used for recording of myoelectrical mechanical activities. Drugs were administered directly into the arterial system of the isolated stomachs either as flash injections or as constant infusions. Flash injection of metoclopramide (Maxeran) led to the response activity (spiking) and associated mechanical response. Electrical control activity was also affected by Maxeran: the changes consisted of premature control activity and uncoupling. Similar reactions were observed after flash injections of methacholine, pentagastrin or electrical stimulation of the Latarjet nerve. These reactions were dose-dependent. Tetrodotoxin, atropine, hexamethonium and glucagon, when given as a constant infusion, did inhibit the action of Maxeran on myoelectrical and mechanical activities of the isolated stomach. Inhibition of the responses to Maxeran by atropine and tetrodotoxin implicates acetylcholine in the mediation of these responses. The ability of hexamethonium to diminish the response to Maxeran suggests that a locus of action may be at both pre- and post-ganglionic sites of the intramural plexus. Exact receptors of this action are not demonstrated by this study.

A canine gastroduodenopancreatic block was isolated and perfused ex vivo with fluorocarbon emulsion, oxygenated in vitro, and containing a simulated physiologic protein-free solution. Pancreatic and gastric secretions were collected. The pancreas was stimulated with secretin or cholecystokinin infused intra-arterially. The response of the pancreas to both hormones was essentially identical to that observed under in vivo conditions or during perfusion of the isolated pancreas with homologous blood. Secretin induced pancreatic secretion was rich in bicarbonate and poor in total protein. Cholecystokinin induced pancreatic secretion contained less bicarbonate and more protein than secretin induced secretion. Differences between secretory responses of the pancreas to these hormones were significant. Gastric secretion was alkaline and contained fluorocarbon emulsion. The results of this study demonstrated that, under the experimental conditions described, external secretory function of the isolated canine pancreas was preserved during perfusion of isolated organs with fluorocarbon emulsion.

A canine gastroduodenopancreatic block was isolated and perfused ex vivo with homologous blood. This preparation allowed a simultaneous collection of gastric and pancreatic secretion under various conditions of stimulation. To stimulate gastric secretion, pentagastrin, bethanechol chloride or histamine was infused intra-arterially during a six to eight hour period, or both vagi were electrically stimulated. To stimulate pancreatic secretion, secretin was infused by the same method. Secretin infusion inhibited gastric juice volume and acid output by stimulated stomachs and induced an increase in pepsin concentration. Secretin infusion also resulted in a significant increase of flow of pancreatic juice and in both concentration and output of pancreatic secretion of bicarbonate. Arterial perfusion pressure and peripheral vascular resistance of this ex vivo preparation were significantly reduced by secretin. The method described permits the simultaneous study of the secretory function of the stomach and pancreas as well as the evaluation of biochemical changes of perfusion blood and hemodynamic changes in the circuit. Easy accessibility of the vessels and vagus branches also allows direct infusion of drugs and placement of stimulation electrodes.

Principal glycoproteins, uronic acid and amino acids were determined in canine gastric secretion, obtained from isolated canine stomachs perfused extracorporeally with homologous blood. Gastric secretion was collected during intraarterial infusion of pentagastrin alone for 3 h, and of secretin + pentagastrin for the next 3 h. Secretin produced a significant increase in the output of D-galactose, D-glucosamine, L-fucose, D-glucose, total sugars, total sulfate and uronic acid. Secretin had no significant effect on the output of most of amino acids of gastric secretion.

This study was concerned with the effects of prostaglandin-E2 (PGE2) on myoelectrical and mechanical activity of the isolated, homologous perfused canine stomach. A flash injection of 25 mug of PGE2 into the gastric artery led to production of premature control potentials, uncoupling of electrical control activity (ECA) and to a weak mechanical response of short duration. After vagal stimulation of the nerve of Latarjet, or after flash injection of pentagastrin (2.5 mug) or of methacholine (5 mug), similar changes in ECA were observed, but mechanical response corresponding to antral contractions was very pronounced. Prolonged infusion of PGE2 (500 mug/h) induced a marked increase of ECA frequency. A similar effect on ECA frequency was observed during infusion of pentagastrin (32 mug/h). Infusion of PGE2 abolished, but infusion of pentagastrin stimulated, mechanical response. Effects of a flash injection of PGE2 on electrical activity were reduced by hexamethonium and abolished by tetrodotoxin and atropine. The action of the blocking agents on PGE2-induced changes in ECA was similar to the action of these blockers on gastric myoelectrical activity, stimulated vagally or by injection of pentagastrin and methacholine. Infusion of PGE2 induced a marked reduction in gastric peripheral vascular resistance, but no time-correlation between hemodynamic effects of PGE2 and its action of gastric musculature was noted.

Totally isolated whole canine stomachs, perfused ex vivo with homologous blood, were used for recording of myoelectrical and mechanical activity. Hormones were administered into the arterial system of the isolated stomach. Pentagastrin, methacholine and electrical stimulation induced premature control potentials with uncoupling of the normal, phase locked, pattern of electrical control activity and also stimulated mechanical activity. Electrical response activity was also present. When the three modes of stimulation were applied during the infusion of glucagon, a marked inhibitory effect was observed. This effect consisted of inhibition of mechanical activity and of electrical response activity. Glucagon also decreased, but did not suppress the changes in electrical control activity observed after electrical stimulation and after injection of pentagastrin or methacholine into the gastric artery of the isolated stomach. During infusion of glucagon, the mean gastric arterial perfusion pressure and gastric peripheral vascular resistance were reduced.

Totally isolated canine stomachs, perfused extracorporeally with homologous blood of living oxygenerator-dogs, were used for the study of gastric secretion. Aminophylline and pentagastrin were infused into the gastric arterial system separately or combined. Aminophylline, infused alone, did not stimulate gastric secretion. However when aminophylline was administered during the infusion of pentagastrin, it significantly augmented the action of this peptide on gastric acid secretion. Aminophylline did not alter myoelectrical and mechanical response to pentagastrin nor did it affect the myoelectrical activity of the nonstimulated stomach. Gastric arterial perfusion pressure and gastric peripheral resistance were reduced during infusion of aminophylline alone or in combination with pentagastrin.

Totally isolated whole porcine stomachs, perfused extracorporeally with homologous blood, were used for recording gastric electrical and mechanical activity. Hormones Hormones were administered into the arterial system of the isolated organ. Pentagastrin, methacholine and electrical stimulation of the vagus nerve induced premature control potentials with uncoupling of the normal, phase-locked, pattern of electrical control activity and also produced electrical response activity and mechanical reaction. When glucagon was infused a progressive decrease of frequency of the cycles of electrical control activity was observed. Glucagon also abolished electrical response activity and mechanical activity, if they were present prior to hormone infusion. When pentagastrin, methacholine or electrical stimulation were applied during the infusion of glucagon, the responses to these stimulants were decreased or absent. The inhibitory action of glucagon was dependent on the duration of infusion of this hormone and lasted for 30-45 min after the infusion was discontinued. During infusion of glucagon the mean gastric arterial perfusion pressure and gastric peripheral vascular resistance were reduced.

Electrical and mechanical activities were recorded from the totally isolated canine stomach perfused with homologous blood of a living oxygenator-supported dog. Stagnant ischemic anoxia was induced by closing inflow and outflow blood from the isolated organ for various periods of time up to four hours. Recording of electrical and mechanical activity was performed prior to, during, and after the anoxic periods. After a given period of ischemia, blood was recirculated for ten minutes, and the pentagastrin was injected into the gastric artery. After up to three hours of anoxia, stomachs were able to show recordable electrical activity when perfused for ten minutes with homologous blood. Up to this period of three hours, stomachs also responded to the injection of pentagastrin. Pentagastrin accelerated the normalization of electrical and mechanical activity of previously anoxic stomachs. After 3.5 to 4.0 hours of anoxia, recirculation of blood through the stomach and injection of pentagastrin had no effect on electrical and mechanical activity of the gastric musculature.

Pentagastrin- and histamine-stimulated secretion of HCl was investigated using isolated canine stomachs perfused ex vivo with homologous blood. The effect of actinomycin D, an inhibitor of DNA-dependent RNA synthesis, on the secretion of HCl by so stimulated stomachs was assessed. The purpose of this experiment was to find whether the trophic action of pentagastrin (RNA synthesis) is interdependent with the secretory action of this hormone. Such interdependence was found in rats by other investigators who reported the suppression of pentagastrin-induced HCl secretion and of RNA synthesis by actinomycin D. Our study did not demonstrate any effect of actinomycin D on pentagastrin-stimulated HCl secretion by isolated canine stomachs. It appears that in dogs the trophic effect of pentagastrin is independent from its secretory action. Review of the literature suggests that the mechanism of gastrin-like hormones on gastric acid secretion in dogs differs from the one found in rats.

Isolated canine stomachs were perfused for 6 h with fluorocarbon emulsion suspended in a simulated physiological solution of electrolytes with glucose added. Gastric mucosa and extramucosal tissues of perfused stomachs were sampled for biochemical analysis of high energy phosphates, glucose and electrolytes. Comparable samples were also taken from normal canine stomachs, dissected under similar surgical conditions as the stomachs used for perfusion. Gastric tissue ATP, ADP and AMP were reduced but CP was increased in the tissues perfused with fluorocarbon as compared with controls. Gastric tissue water content and sodium were increased but potassium was reduced in a stomach so perfused. The biochemical tests performed were considered as viability tests of organs preserved-perfused in fluorocarbon prior to possible transplantation. Significance of the changes observed is discussed in the light of the current knowledge on energy metabolism.

Totally isolated whole canine stomachs, perfused ex vivo with homologous blood, were used for recording of myoelectrical and mechanical activity prior to and following the injection of secretin. Secretin was given as flash injections (0.5 - 32 U) or constant infusions (60 U/h). Background stimulation of stomachs was obtained by intragastric instillation of fluid, by the infusion of pentagastrin or bethanechol chloride, and by electrical stimulation of the Latarjet branch of the vagus nerve. Hormones were injected into the gastric arterial circulation. Secretin had no effect on the frequency of electrical control activity. Secretin inhibited electrical response activity when injected against the background of electrical vagus stimulation. Secretin also inhibited or decreased mechanical activity of the gastric antrum, recorded at the site of the antral strain gauge.