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At least 1,279 records · Page 71Linked to original sources
PubMed1976

Effect of motilin on the lower oesophageal sphincter.

The effect of motilin on lower oesophageal sphincter (LES) pressure has been studied in unanesthetised specially trained dogs using an infusion manometric technique. Motilin produced significant rises in resting pressure and contractions of the LES after doses ranging from 0-009 mug/kg to 0-05 mug/kg. Doses greater than 0-05 mug/kg resulted in repetitive high amplitude contractions. Atropine 30 mug/kg completely abolished the effect of the lower doses of motilin. Higher doses of motilin in atropinised dogs still caused a small rise in baseline pressure and contractile activity still appeared. Hexamethonium 2 mg/kg resulted in both a diminished rise in LES pressure and the disappearance of contractions after motilin. Hexamethonium and atropine together completely abolished the LES response to motilin. We conclude that motilin increases LES pressure by acting on preganglionic cholinergic neurones to release acetylcholine which excites other cholinergic neurones supplying the circular muscle of the LES.

Animals↗
PubMed1981

Ultrastructure of endocrine-like cells in lamina propria of human gastric mucosa.

Endocrine cells of gastric and gut mucosa are commonly thought to be present only within mucosal glands. In a previous report, we described argyrophilic cells in the lamina propria in 40% of surgical gastric specimens, using light microscopy. All these patients had chronic gastritis. Argyrophilia, however, is a non-specific reaction which could occur in other than endocrine cells. The present study was undertaken to describe the ultrastructure of argyrophil cells in the lamina propria. In five patients with chronic gastritis, endoscopic biopsies were taken from the fundic, intermediate, and pyloric areas of the stomach. Single and/or clustered argyophil cells were seen by light microscopy in the lamina propria of the intermediate and pyloric areas. On electron-microscopy, these cells had the following characteristics of endocrine-like cells: they were characterised by numerous electron dense granules in the cytoplasm, 100-300 nm in diameter; the cytoplasm contained poorly-developed rough endoplasmic reticulum and well-developed smooth endoplasmic reticulum with occasional vesicles. Immunostaining gave negative results for various gastrointestinal hormones. These ultrastructural characteristics of lamina propria cells are similar to endocrine cells of the APUD series. We conclude that endocrine-like cells occur in the lamina propria of the human stomach in the presence of chronic gastritis.

Adult↗
PubMed1983

Effect of secretin, pancreozymin OP-CCK, and glucagon on bile flow and bile lipid secretion in rats.

Rats equipped with biliary, duodenal, and vena cava cannulae and supplemented with Na taurocholate received 4 hour infusions of gastrointestinal hormones. Boots secretin increased bile flow by 63% and bile acid, cholesterol, and phospholipid output by 75, 96, and 73% respectively. This stimulatory effect on bile flow and bile acid secretion was observed also in the four hour postinfusion period. Kabi secretin had practically no effect on bile secretion. Boots pancreozymin stimulated bile flow by 45% and to some extent also stimulated bile acid output. OP-CCK and glucagon stimulated mainly bile flow rate.

Animals↗
PubMed1988

Further characterisation of the 'ileal brake' reflex in man--effect of ileal infusion of partial digests of fat, protein, and starch on jejunal motility and release of neurotensin, enteroglucagon, and peptide YY.

Previous studies have shown that ileal infusion of partially digested triglyceride inhibits jejunal motility. The partial digest used in those studies contained a mixture of glycerol, free fatty acid, mono-, di-, and triglycerides. In Part I of the present study we have separately infused emulsions containing either glycerol 3.1 g (n = 6), oleic acid 9.6 g (n = 6), triolein 10 g (n = 12), or medium chain triglycerides 10 g (n = 6) into the ileum and have recorded the effect this has on jejunal motility. Five further subjects received infusions of partial hydrolysates of corn starch 10 g and lactalbumin 7 g. Marked inhibition of jejunal pressure wave activity was seen after all three lipid infusions, per cent activity falling from a control of 37.7 (7.7) to 6.2 (2.1) and 22.4 (8.2)% 30 min after completing the oleic acid and triolein infusions respectively, and from a control value of 39.5 (4.1) to 17.7 (4.7) after MCTs (all p less than 0.05). No significant fall occurred after infusion of glycerol, protein or carbohydrate. All three lipid infusions raised plasma concentrations of neurotensin, enteroglucagon and peptide YY equally effectively, although only the rise in peptide YY correlated significantly with the inhibition of jejunal pressure wave activity (r = 0.80, n = 6, p less than 0.05). In Part II of this study six subjects received a 3 ml/min jejunal infusion of an isotonic carbohydrate saline solution followed after three hours by a similar infusion of a partial digest of lipid. During each infusion flow and transit time was measured by marker and dye dilution. Jejunal infusion of the carbohydrate-saline solution was associated with low jejunal flow, 4.7 (1.0) ml/min and a mean transit time through the 50 cm study segment of 36.5 (7.1) min. By contrast jejunal infusion of partially digested triglyceride was associated with a markedly increased flow, 9.0 (1.2) ml/min, a fall in mean transit time to 20.3 (2.6) min and significant rises in pancreaticobiliary secretions. Jejunal triglyceride also increased the incidence of prolonged high amplitude jejunal pressure waves in four of six subjects. These studies suggest that there are important differences in the jejunal response to ileal versus jejunal lipid. While long and median chain free fatty acids infused into the ileum exert an inhibitory effect on jejunal motility, when infused directly into the jejunum partially digested triglyceride accelerates transit, increases jejunal flow and subtly alters the pattern of jejunal contractions.

Adult↗
PubMed1993

Bile salt inhibition of motility in the isolated perfused rabbit terminal ileum.

The effects of bile on small bowel motility were studied in isolated, perfused rabbit terminal ileum. It was proposed that bile delivery into the distal ileum would inhibit ileal motor activity, by peptide YY (PYY) release and therefore the effect of luminal bile on motor activity was examined and PYY release measured. Luminal bile and taurocheodeoxycholic acid (10 mmol) inhibited ileal motor activity. Arterial infusion of venous effluents from a bile inhibited ileum suppressed motor activity in a second isolated ileum. This shows the presence of a humoral inhibitor of ileal motor activity. Luminal bile increased venous PYY concentrations (42.5 (8.5) to 502 (46.2) pmol/l; p < 0.01) and increased bile salt values (1.7 (0.36) to 88.6 (5.6) 10 mumol/l/l; p < 0.005). Arterial infusion of taurocheodeoxycholic acid at concentrations found in the venous effluent (100 mumol/l/l) suppressed motility (p < 0.001) but infusion of PYY at concentrations in the venous effluent (500.0 pmol/l) failed to inhibit motility. Furthermore, PYY antagonist, PYX 1, failed to reverse the bile induced inhibition of motility. Luminal bile salts inhibit terminal ileal motility and this is independent of PYY release. By slowing motility, bile salts may participate in their own absorption by the 'ileal pump' and in the 'ileal brake' mechanism.

Animals↗
PubMed2001

Pancreatic surgical complications--the case for prophylaxis.

Pancreaticoduodenectomy (Whipple's procedure) represents a considerable surgical challenge. Postoperative complications are common and typically related to leakage of pancreatic exocrine secretions following anastomosis failure. Pancreatic proteases and lipase leaking from the organ remnant attack the surrounding tissue, potentially leading to severe inflammation, tissue necrosis, and fistula formation. In addition, the soft consistency of the normal pancreas can lead to difficulties in manipulating the organ and reduce the integrity of sutures. Pancreatic fistula is the most serious postoperative complication and especially common following resectional surgery for malignant disease. Through prophylactic inhibition of digestive secretions, it should be possible to reduce postoperative morbidity after pancreatic surgery. One such inhibitor is somatostatin-14, an endogenous peptide hormone with pronounced effects on secretion of pancreatic enzymes and hormones, gastrointestinal secretions, and pancreatic blood flow, all of which may decrease the risk of postoperative complications. A limited number of randomised controlled trials have investigated prophylactic administration of somatostatin-14 and the synthetic somatostatin analogue octreotide in reducing complications following pancreatic surgery. While the majority of studies with octreotide demonstrated a significant reduction in the overall complication rate, the benefits appeared less marked in relation to events specifically related to pancreatic secretion. However, preliminary results from a limited number of trials with somatostatin-14, administered as a continuous intravenous infusion, suggest that prophylactic pharmacotherapy produces a significant decrease in fistula formation and secretion related events after pancreaticoduodenectomy. Due to these promising data, further investigation of the role of somatostatin-14 prophylaxis in pancreatic surgery is warranted in large well controlled trials.

Clinical Trials as Topic↗
PubMed1982

Development of the pancreas during gestation and lactation in swine.

This study examined the development of the pancreas during gestation and lactation in swine. Forty-two mated sows and 42 unmated controls were sacrificed after 30, 70, and 110 days of gestation; 7, 14, and 28 days of lactation; and 11 days after weaning. Their pancreas were excised, weighed, and fragments homogenized for evaluation of protein, amylase, chymotrypsin, RNA, and DNA contents. Data indicate that all these parameters were reduced at the end of the gestation period when compared with controls. During lactation, pancreatic weights, enzyme, protein, and RNA contents showed regular increases. DNA contents were significantly increased after weaning, an indication of pancreatic hyperplasia. A return to control values is not complete 11 days after weaning. These changes in the pancreas can be related to increased food intake during lactation and are probably mediated by the endogenous release of the gastrointestinal hormones cholecystokinin and secretin.

Amylases↗
PubMed1983

Cholinergic control mechanisms for immunoreactive motilin release and motility in the canine duodenum.

The relationship of immunoreactive (IR) motilin release from the duodenum to duodenal motility changes was investigated in anaesthetized dogs. Stimulation of one or both vagi at 5 or 15 Hz or field stimulation of intrinsic duodenal nerves produced significant increases in duodenal vein IR motilin concentrations and accompanying increases in duodenal motility. However, only stimulation of both vagi at 15 Hz produced significant changes in peripheral venous concentrations of IR motilin. These occurred after a delay at a time when both the duodenum and the antrum were quiescent. Either hexamethonium or atropine blocked IR motilin release induced by stimulation of intrinsic or extrinsic nerves while only atropine inhibited the release induced by intraarterial carbachol. The response stimulated by carbachol and blocked by atropine was tetrodotoxin insensitive and the muscarinic receptor involved was presumably located on a nonneural structure. The site sensitive to hexamethonium was presumably the neural pathway which terminated at the muscarinic receptor. Concomitant studies of duodenal motility responses to vagal and field stimulation suggested a conventional neural pathway with preganglionic cholinergic nerves in the vagus, postganglionic cholinergic nerves in the duodenum (activated by field stimulation) and a smooth muscle muscarinic receptor. Activation of antral motility by stimulation of the abdominal vagus or intraarterial carbachol injections to the antrum increased duodenal IR motilin release in the absence of duodenal motility. Thus activation of the intrinsic nerves which cross the pylorus initiated IR motilin release as well as inhibited duodenal motility.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Vagal control of migrating motor complex-related peaks in canine plasma motilin, pancreatic polypeptide, and gastrin.

The role of the vagus nerve in the control of fasting plasma pancreatic polypeptide (PP), gastrin, and motilin levels was investigated in conscious dogs. Lowest plasma levels of motilin (81 +/- 8 pmol/L), PP (19 +/- 1 pmol/L) and gastrin (5 +/- 1 pmol/L) were observed during phase I of the migrating motor complex (MMC). Significant peaks in plasma motilin (127 +/- 11 pmol/L, P less than 0.005), PP (26 +/- 2 pmol/L, P less than 0.005), and gastrin (14 +/- 2 pmol/L, P less than 0.005) were seen, coinciding with the appearance of phase II (PP and gastrin) or phase III (motilin) of the migrating motor complex in the upper gut. Whereas bilateral vagal blockade abolished the peaks in PP and gastrin, a significant (P less than 0.025) increment in plasma motilin remained, which correlated with the late phase III equivalent of the vagally independent complex (VIC) in the duodenum. This VIC-related motilin peak (170 +/- 20 pmol/L) was significantly higher (P less than 0.025) and the time course (9 +/- 2 min) significantly shorter (P less than 0.01) than the peak (127 +/- 11 pmol/L) and duration (31 +/- 9 min) observed without vagal blockade. Thus, in fasting, the cyclical increments of PP and gastrin are both dependent on excitatory vagal innervation, whereas excitatory pathways controlling phase III associated peak motilin release are nonvagal. In addition, the pattern of fasting motilin release and the amplitude of peak motilin secretion may be affected by vagal inhibition.

Animals↗
PubMed1984

Motilin and the vagus in dogs.

The aim of this work was to determine the influence of the vagus on the circulating levels of immunoreactive (IR) motilin. Five mongrel dogs were equipped with chronically implanted electrodes in the small intestine to record the myoelectrical activity. The release of IR motilin during fasting, after a meal, and during an infusion of insulin was studied before and after truncal vagotomy at the diaphragmatic level. When tested at least two weeks after the operation, the motility pattern of the small intestine and the secretion of IR motilin remained unaltered by vagal section. Cyclic increases in IR motilin associated with phase III's of the interdigestive myoelectric complexes were still observed after vagotomy (maximum levels of IR motilin: 250 +/- 37 versus 239 +/- 19 fmol X mL-1, not significant), and they were still abolished by feeding or by insulin. However, an inhibitory influence can probably be mediated by the vagus since, in normal animals, vagal stimulation by a "modified sham feeding" (tease feeding or presentation of food) at the beginning of a period of phase III activity promptly interrupted this part of the complex and decreased significantly the release of IR motilin by about 20%. The release of motilin is not chronically altered by distal vagotomy in dogs.

Animals↗
PubMed1993

Spinal modulation of duodenal and colonic motility and arterial pressure by neuropeptide Y, neuropeptide Y fragment 13-36, peptide YY, and pancreatic polypeptide in rats: involvement of the cholinergic nervous system.

The pancreatic polypeptide-fold (PP-fold) peptides, peptide YY (PYY) and pancreatic polypeptide (PP) (200 pmol), increased duodenal intraluminal pressure following intrathecal (IT) administration into the thoracic (T8-T10) spinal cord of urethane-anesthetized rats. Neuropeptide Y (NPY), PPY, and PP (IT) increased colonic intraluminal pressure of rats. The excitatory effects of the PP-fold peptides, NPY and PYY, were accompanied by increases in mean arterial pressure (MAP) during the same time period followed by a decrease to hypotensive levels. There were no further alterations of duodenal or colonic pressure in rats during the hypotensive period. The effect of PP (IT) on MAP was characterized by a pattern of hypotension frequently followed by a hypertensive period. The modulation of duodenal and colonic pressure does not differ between the members of the PP-fold family of peptides; however, the effects of the different members of the PP-fold family of peptides on MAP were varied. The Y2 receptor ligand, NPY (13-36) (200 pmol) (IT), did not alter duodenal and colonic pressure or MAP in rats. Therefore, the effects of PYY and NPY in the thoracic spinal cord on duodenal and colonic motility may be mediated via Y1 (postjunctional) receptors. Atropine, a muscarinic antagonist, attenuated NPY's (IT) excitatory effect on colonic pressure but did not alter the MAP response to this peptide. Atropine did not modify PYY's (IT) regulation of duodenal and colonic intraluminal pressure. However, atropine did attenuate PPY's inhibitory effect on MAP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗