A quantitative study of the effects of anaesthesia and stress of operation on gastric secretion in rats

Ether anaesthesia, present from 5 min before to 5 min after pyloric occlusion, significantly reduced gastric secretion in rats observed over a period of 2 hr. The reduction in gastric secretion was similar to that caused by surgical trauma resulting from acute pyloric ligation. The inhibitory effects induced by ether anaesthesia were found to wear off after 2 hr while those caused by surgical trauma persisted for 5 hr. These findings show conclusively that both surgical trauma and ether anaesthesia will depress gastric secretion in rats which are operated upon immediately before use in gastric secretory studies. Such effects are not present with the technique for pyloric occlusion described by the present authors.     

An explanation of gastric hypersecretion in the pylorus-ligated rat

The hypersecretion of gastric acid in the pylorus-ligated rat has been shown to be of vagal origin. The present series of experiments were performed to identify the stimulus. The pyloric sphincter was ligated in a series of Sprague Dawley rats. Along with pylorus ligation, various other surgical manipulations were performed. Intestinal obstruction by ligation approximately 20 cm aboral to the cecum reduced unstimulated gastric secretion in the pylorus-ligated rat. However, perfusion of the lower small intestine with bicarbonate (143 mEq/L) stimulated secretion. Perfusion with either saline or deoxycholic acid (20 mEq/L) did not alter secretion. This supports a role for bicarbonate in the hypersecretion of gastric acid in the pylorus-ligated rat. The reflex appears to involve the myenteric plexus, since section of the pylorus seemed to attenuate gastric secretion. Plasma from animals with pylorus ligation, either alone or with intestinal ligation, equally inhibited gastric secretion. This suggests that while some factor inhibiting gastric secretion may be present, it appears to be unrelated to pylorus ligation.     

Hypertrophic pyloric stenosis

Hypertrophic pyloric stenosis, a relatively common condition, is caused by hyperplasia of the musculature of the pylorus. The diagnosis is made by a history of projectile vomiting and failure to gain weight, the observation of gastric peristaltic waves, and the palpation of a pyloric "tumor." A method of palpating this tumor is described in detail. Roentgenological studies are rarely indicated. Pylorotomy for treatment of hypertrophic pyloric stenosis was not successful until the development of necessary supporting measures. Preparation for operation consists of intravenous administration of fluids and electrolytes and sometimes serum or whole blood. The position of the tumor governs the choice between two different incisions. The operative procedure herein described is essentially that devised by Ramstedt many years ago, with modifications to facilitate the procedure.     

尖顶羊肚菌菌丝体水提液对实验型胃溃疡的作用

研究尖顶羊肚菌菌丝体水提液对4种实验型胃溃疡模型的治疗作用。以大鼠幽门结扎致胃溃疡为模型,测定各组胃粘膜损伤指数、胃液分泌量和胃酸浓度;以大鼠乙酸烧灼、小鼠乙醇致胃粘膜损伤和小鼠水浸应激胃溃疡为模型,分别测定溃疡面积。结果表明尖顶羊肚菌菌丝体水提液可以不同程度抑制胃酸的分泌,减少胃液量,减少溃疡面积,促进溃疡面积的愈合,因此尖顶羊肚菌菌丝体水提液具有抗实验型胃溃疡的作用。     

Antiulcerogenic activity of Satavari mandur--an Ayurvedic herbo-mineral preparation

Satavari mandur (SM) is a herbo-mineral preparation containing Asparagus racemosus, which finds mention in ancient Indian texts for treatment of gastric ulcers. The ulcer protective effect of SM, 125-500 mg/kg given orally, twice daily for three, five and seven days, was studied on cold restraint stress-induced gastric ulcer in rats. The effective regimen was found to be 250 mg/kg given for five days and hence was used for further experiments. SM showed significant protection against acute gastric ulcers induced by pyloric ligation but was ineffective against aspirin- and ethanol-induced ulcers. Further, gastric juice studies showed that, SM significantly increased the mucosal defensive factors like mucus secretion, but had little or no effect on offensive factors like acid and pepsin secretion.     

Alkaloids from Mahonia bealei posses anti-H+/K+-ATPase and anti-gastrin effects on pyloric ligation-induced gastric ulcer in rats

The purpose of this study was to investigate the underlying mechanism(s) of the total alkaloids (TA) from Mahonia bealei in treating pyloric ligation-induced gastric ulcers in rats. Animals were sacrificed after 19 h of the ligation. Gastric acid, peptic activities, mucin levels, H⁺/K⁺-ATPase activities and the gastrin level were analyzed. To improve the accuracy of the observations, IPP 6.0 software was introduced to measure the area of ulcer. TA (18.56 mg/kg/day, i.g.) showed an antiulcer effect by significantly decreasing the gastric ulcer areas (11.28 mm²) compared with model group (26.36 mm²). The TA ulcer inhibition ratio was 57.2%, compared with the effect of the positive control, omeprazole (62.96%). The results also showed that TA had a significant effect in inhibiting the release of H⁺/K⁺-ATPase, reducing the content of gastrin and decreasing gastric acidity on experimental animals. However, the TA had no significant effects on gastric mucus secretion and pepsin activity. Data indicated that TA had gastric ulcer protective effects by modulating the H⁺/K⁺-ATPase activity and gastrin level. TA has a potential to be developed as a pharmacological agent for the treatment of gastric ulcers.     

Pyloric gastrin-producing cells and pyloric sphincter muscle cells are nuclear targets for 3H 1,25(OH)2 vitamin D3. Studied by autoradiography and immunohistochemistry

Autoradiographic studies were conducted to identify and characterize target cells for 1,25(OH)2 vitamin D3 in the pyloric region of rats and mice. After injection of 3H 1,25(OH)2 vitamin D3, nuclear concentration of radioactivity was observed in nuclei of duodenal epithelium and certain cells of pyloric glands, while most of the epithelial cells in the pyloric and gastric glands did not show nuclear labeling. In combined immunohistochemical studies, cells in the pyloric glands that showed nuclear concentration of radioactivity, were stained in their cytoplasm with antibodies to gastrin. Also, cells of the pyloric sphincter muscle showed nuclear labeling, in contrast to cells of the duodenal muscularis, which remained unlabeled under the conditions of the experiments. The results indicate that the cells with nuclear radioactivity contain receptors for 1,25(OH)2 vitamin D3 and suggest that gastrin secretion and pyloric muscle functions are regulated by a direct action of 1,25(OH)2 vitamin D3 on these cells.     

Inhibitory effects and mechanisms of intestinal electrical stimulation on gastric tone, antral contractions, pyloric tone, and gastric emptying in dogs

The aim of this study was to investigate the effects and mechanisms of intestinal electrical stimulation (IES) on gastric tone, antral and pyloric contractions, and gastric emptying in dogs. Female hound dogs were equipped with a duodenal or gastric cannula, and one pair of serosal electrodes was implanted in the small intestine. The study consisted of five different experiments. Liquid gastric emptying was assessed by collection of chyme from the duodenal cannula in a number of sessions with and without IES and with and without N-nitro-l-arginine (l-NNA). Postprandial antral and pyloric contractions were measured with and without IES and in the absence and presence of l-NNA or phentolamine by placement of a manometric catheter into the antrum and pylorus via the duodenal cannula. Gastric tone was assessed by measurement of gastric volume at a constant pressure. Gastric emptying was substantially and significantly delayed by IES or l-NNA compared with the control session. IES-induced delay of gastric emptying became normal with addition of l-NNA. IES reduced gastric tone, which was blocked by l-NNA. IES also inhibited antral contractions (frequency and amplitude), and this inhibitory effect was not blocked by l-NNA but was blocked by phentolamine. IES alone did not affect pyloric tone or resistance, but IES + l-NNA decreased pyloric tone. In conclusion, IES reduces gastric tone via the nitrergic pathway, inhibits antral contractions via the adrenergic pathway, does not affect pyloric tone, and delays liquid gastric emptying. IES-induced delay of gastric emptying is attributed to its inhibitory effects on gastric motility.     

Pyloric gastrin-producing cells and pyloric sphincter muscle cells are nuclear targets for 3H 1,25(OH)2 vitamin D3

Summary Autoradiographic studies were conducted to identify and characterize target cells for 1,25(OH)₂ vitamin D₃ in the pyloric region of rats and mice. After injection of ³H 1,25(OH)₂ vitamin D₃, nuclear concentration of radioactivity was observed in nuclei of duodenal epithelium and certain cells of pyloric glands, while most of the epithelial cells in the pyloric and gastric glands did not show nuclear labeling. In combined immunohistochemical studies, cells in the pyloric glands that showed nuclear concentration of radioactivity, were stained in their cytoplasm with antibodies to gastrin. Also, cells of the pyloric sphincter muscle showed nuclear labeling, in contrast to cells of the duodenal muscularis, which remained unlabeled under the conditions of the experiments. The results indicate that the cells with nuclear radioactivity contain receptors for 1,25(OH)₂ vitamin D₃ and suggest that gastrin secretion and pyloric muscle functions are regulated by a direct action of 1,25(OH)₂ vitamin D₃ on these cells.     

The endocrine cells of the upper gut mucosa in dogs with transplantation of the pyloric antrum to the colon

Summary A previous examination, done by others, of the endocrine cells of the canine pyloric antrum following its transplantation to the colon evidenced an increase in their number; the cell types involved, however, were not individualized. The present study further characterizes the changes occurring in the endocrine cells of the pyloric antrum of dogs following transplantation to the colon. The main change observed consists of hyperplasia of the enterochromaffin cells, with minor qualitative modifications in the antral gastrin-producing cells being noted only by electron microscopy. The response of the enterochromaffin cells cannot be readily explained but might be related to similar enterochromaffin cell hyperplasias found in human stomachs with peptic ulcers. Antrum transplantation to the colon in dogs appears to provide a promising experimental model for the study of the relationship between gastrin and other humoral factors (probably biogenic amines) in the mechanism of gastric secretion under normal as well as abnormal circumstances.Supported by a grant from the Medical Research Council of Canada. While performing this research, Dr. J. Lechago was a recipient of a fellowship from the Medical Research Council of Canada.     

Antiulcerogenic potential of Strychnos potatorum Linn seeds on Aspirin plus pyloric ligation-induced ulcers in experimental rats

Strychnos potatorum (Fam: Loganiaceae) Linn seeds are useful in the treatment of gastropathy in Indian traditional system of medicine. The present study describes the antiulcerogenic potential of S. potatorum Linn seeds on aspirin plus pyloric ligation (Aspirin+PL)-induced gastric ulcer model to substantiate its folklore claim. The seed powder (SPP) and aqueous extract of the seeds (SPE) at two doses 100 and 200 mg/kg, p.o. prevented ulcer formation by decreasing acid secretory activity and increasing the mucin activity in rats. The antiulcerogenic potential was further confirmed by the histopathological studies of stomach mucosa. The results indicate that SPP and SPE exhibit antiulcerogenic activity by both antisecretory and mucoprotective actions. The mucoprotective action of SPP and SPE may be due to the presence of polysaccharides in seeds. The antiulcerogenic potential of SPP and SPE was compared with the standard antiulcer drug, ranitidine.     

Histological description of the midgut and the pyloric valve of Tropidacris collaris (Stoll, 1813) (Orthopetera: Romaleidae).

The present research describes the histology of the midgut, gastric caeca, and pyloric valve of Tropidacris collaris (Stoll, 1813), (Orthopetera: Romaleidae). We used light microscopy, staining (Gomori's trichrome and periodic acid-Schiff (PAS)), and a routine histological analysis method (hematoxilin-eosin). The insects were obtained from, and also bred in, the Laboratory of Entomology, Department of Biology, of the Rural Federal University of Pernambuco (UFRPE). The collected material was fixed in alcoholic Botüin and embedded in paraplast. The results demonstrated that the midgut wall is composed of an inner epithelial layer and two outer layers of striate muscles: one internal (circular) and the other external (longitudinal), with connective tissue between the muscle fibers. The epithelium is single-layered, with two cell types: regenerative and elongated columnar. The gastric caeca presents muscle layers similar to those of the midgut. Simple columnar epithelium lines the gastric caeca, which presents villi and projects towards the lumen. The pyloric valve is of striate muscle tissue, covered by a single epithelial-cell layer.     

Clinical diagnosis of pyloric stenosis: a declining art.

OBJECTIVE--To assess whether diagnostic imaging of pyloric stenosis has made a difference in rapidity of diagnosis, duration of pre-operative hydration, and length of stay in hospital. DESIGN--Chart review of infants with confirmed diagnosis of pyloric stenosis. SETTING--Paediatric teaching hospital. SUBJECTS--215 infants with a confirmed diagnosis of pyloric stenosis seen during 1974-7 and 187 infants with pyloric stenosis seen during 1988-91. MAIN OUTCOME MEASURES--State of hydration on admission, time between presentation to hospital and a definite diagnosis, techniques used to make the diagnosis, whether a pyloric mass was felt before or after an imaging procedure, time between presentation and surgery, and length of stay in hospital. RESULTS--The average age at presentation was 40 days in both groups. A pyloric mass was palpated either without or before an imaging study in 87% (187/215) of cases during 1974-7 but in only 49% (91/187) during 1988-91. The use of barium meal examination and ultrasonography increased from 20% (42/215) of cases during 1974-7 to 61% (114/187) during 1988-91. There were no significant differences between the two groups in the time taken to establish a diagnosis, the mean duration of preoperative treatment, or the length of stay in hospital (after allowance for the decline in average length of stay of all hospital patients between the two periods). CONCLUSIONS--An increased use of diagnostic imaging for pyloric stenosis did not lead to earlier diagnosis or better management. While imaging is important in identifying pyloric stenosis in difficult cases, increasing reliance on imaging has reduced doctors'' skills in diagnosing pyloric stenosis clinically.     

Effect of dothiepin on gastric ulceration mediated by lipid derived eicosanoids

Dothiepin, a tricyclic antidepressant, significantly inhibited the development of gastric ulcers induced by alcohol, aspirin, indomethacin and Shay's pyloric ligation. Antisecretory studies in pyloric ligated rats revealed that the drug at a dose of 100 mg/kg significantly reduced total acidity, gastric output and protein content. In another set of experiments, dothiepin significantly reduced gastric output, total acidity and protein content in pyloric ligated rats which received 50% alcohol (v/v) 30 minutes after the administration of dothiepin.     

Alkaline elution of DNA from stomach pyloric mucosa of rats treated with glyoxal

DNA damage in the pyloric mucosa of the stomach of male F344 rats was determined by the alkaline elution method after administration of glyoxal, a direct-acting mutagen present in various heated foods, by gastric intubation. Glyoxal at doses of 50-550 mg/kg body weight induced DNA damage in the pyloric mucosa of rat stomach, detected by a 5- to 12-fold increase in the elution rate constant 2 h after its administration. N-Methyl-N'-nitro-N-nitrosoguanidine, a glandular stomach carcinogen, used as a positive control at doses of 1-100 mg/kg body weight induced a 11- to 24-fold increase in the elution rate constant, while 2-acetylaminofluorene, which is not a gastric carcinogen, given as a negative control at doses of 200-400 mg/kg body weight did not increase the elution rate constant. Thus glyoxal, which was previously suggested to induce unscheduled DNA synthesis in the pyloric mucosa of rat stomach, was confirmed to be genotoxic in this region.     

Role of ghrelin in the regulation of gastric acid secretion involving nitrergic mechanisms in rats

Ghrelin, an endogenous ligand for growth hormone secretagogue receptor (GHS-R), has been identified in the rat and human gastrointestinal tract. Ghrelin has been proposed to play a role in gastric acid secretion. Nitric oxide (NO) was shown as a mediator in the mechanism of ghrelin action on gastric acid secretory function. However, there is a little knowledge about this topic. We have investigated the role of ghrelin in gastric acid secretion and the role of NO as a mediator. Wistar albino rats were used in this study. The pyloric sphincter was ligated through a small midline incision. By the time, saline (0.5 ml, iv) was injected to the control group, ghrelin (20 microg/kg, iv) was injected to the first experimental group, ghrelin (20 microg/kg, iv) + L-NAME (70 mg/kg, sc) was injected to the second group and L-NAME (70 mg/kg, sc) was administered to the third group. The rats were killed 3 h after pylorus ligation; gastric acid secretion, mucus content and plasma nitrite levels were measured. Exogenous ghrelin administration increased gastric acid output, mucus content and total plasma nitrite levels, while these effects of ghrelin were inhibited by applying L-NAME. We can conclude that ghrelin participates in the regulation of gastric acid secretion through NO as a mediator.     

Inhibitory effects of botulinum toxin on pyloric and antral smooth muscle

Botulinum toxin injection into the pylorus is reported to improve gastric emptying in gastroparesis. Classically, botulinum toxin inhibits ACh release from cholinergic nerves in skeletal muscle. The aim of this study was to determine the effects of botulinum toxin on pyloric smooth muscle. Guinea pig pyloric muscle strips were studied in vitro. Botulinum toxin type A was added; electric field stimulation (EFS) was performed every 30 min for 6 h. ACh (100 microM)-induced contractile responses were determined before and after 6 h. Botulinum toxin caused a concentration-dependent decrease of pyloric contractions to EFS. At a low concentration (2 U/ml), botulinum toxin decreased pyloric contractions to EFS by 43 +/- 9% without affecting ACh-induced contractions. At higher concentrations (10 U/ml), botulinum toxin decreased pyloric contraction to EFS by 75 +/- 7% and decreased ACh-induced contraction by 79 +/- 9%. In conclusion, botulinum toxin inhibits pyloric smooth muscle contractility. At a low concentration, botulinum toxin decreases EFS-induced contractile responses without affecting ACh-induced contractions suggesting inhibition of ACh release from cholinergic nerves. At higher concentrations, botulinum toxin directly inhibits smooth muscle contractility as evidenced by the decreased contractile response to ACh.     

Effects of cholecystokinin on appetite and pyloric motility during physiological hyperglycemia

Recent studies suggest that the interaction between small intestinal nutrient stimulation and the blood glucose concentration is important in the regulation of gastric motility and appetite. The purpose of this study was to determine whether the effects of cholecystokinin octapeptide (CCK-8) on antropyloric motility and appetite are influenced by changes in the blood glucose concentration within the normal postprandial range. Seven healthy volunteers were studied on 4 separate days. A catheter incorporating a sleeve sensor was positioned across the pylorus, and the blood glucose was stabilized at either 4 mmol/l (2 days) or 8 mmol/l (2 days). After the desired blood glucose had been maintained for 90 min, an intravenous infusion of either CCK-8 (2 ng. kg(-1). min(-1)) or saline (control) was given for 60 min. Thirty minutes after the infusion began, the catheter was removed and subjects drank 400 ml of water with guar gum before being offered a buffet meal. The amount of food consumed (kcal) was quantified. The order of the studies was randomized and single-blinded. There were fewer antral waves at a blood glucose of 8 than at 4 mmol/l during the 90-min period before the infusions (P<0.05) and during the first 30 min of CCK-8 or saline infusion (P = 0.07). CCK-8 suppressed antral waves (P<0.05), stimulated isolated pyloric pressure waves (IPPWs) (P<0.01), and increased basal pyloric pressure (P<0.005) compared with control. During administration of CCK-8, basal pyloric pressure (P<0.01), but not the number of IPPWs, was greater at a blood glucose of 8 mmol/l than at 4 mmol/l. CCK-8 suppressed the energy intake at the buffet meal (P<0.01), with no significant difference between the two blood glucose concentrations. We conclude that the acute effect of exogenous CCK-8 on basal pyloric pressure, but not appetite, is modulated by physiological changes in the blood glucose concentration.     

Monoclonal antibody specific to urochordate Botryllus schlosseri pyloric gland

We describe here the development of a new hybridoma cell line, CF12F6, that produces a specific antibody to Botryllus schlosseri (a colonial tunicate). The monoclonal antibody was isotyped as IgG1 (by enzyme-linked immunosorbent assay), and the cellular localization of the antigenic epitope that reacts specifically with CF12F6 was confined to the cells of the pyloric gland of the zooid (by immunohistochemistry). The pyloric gland participates in osmoregulation, digestion, glycogen storage, and various other secretion functions that will be studied further by the use of monoclonal antibody CF12F6, the first in botryllid ascidians that recognizes cells of a whole, single organ.     

Effect of proximal selective vagotomy on gastric prostaglandin content in the Shay-rat ulcer model

During Shay-ulcer formation damages to the barrier of the gastric mucosa develop even before the appearance of macroscopic ulceration. Proximal selective vagotomy prevents these damages. Following pyloric ligation the prostaglandin content of the mucosa changes in parallel with the injuries of the mucosal barrier: TXB2 content of the forestomach increases, while PGF2 alpha content of both the forestomach and the antrum decreases. Following PSV operation the 6-keto-PGF1 alpha content of the mucosa decreases, whereas PGF2 alpha and TXB2 contents exhibit no alteration. As a combined effect of proximal selective vagotomy pretreatment and pyloric ligation the 6-keto-PGF1 alpha and PGF2 alpha contents of the mucosa remain low and the TXB2 increase, otherwise detectable after pyloric ligation, does not take place.