sincalide and Stomach-Ulcer

Leptin was shown to exhibit similar to cholecystokinin (CCK) cytoprotective activity against acute gastric lesions, but its role in ulcer healing has not been examined. The aims of this study were: (1) to compare the effects of exogenous leptin to those of CCK on the course of healing of chronic gastric ulcers; (2) to study the gene and protein expression of leptin at the ulcer margin during ulcer healing; and (3) to assess the effects of leptin administration on the mucosal gene expression of main growth factor such as transforming growth factor alpha (TGFalpha). Gastric ulcers were produced in rats by the acetic acid method. Rats with ulcers were divided in following treatment groups: (1) vehicle; (2) leptin (10 microg/kg i.p.); (3) CCK (10 microg/kg s.c.); and (4) leptin or CCK with or without tyrphostin A46 (200 microg/kg i.p.), an inhibitor of epidermal growth factor (EGF)-receptor tyrosine kinase or NG-nitro-L-arginine (20 mg/kg i.g.), a blocker of nitric oxide synthase. Animals were euthanized 9 days after ulcer induction. The area of gastric ulcers and the gastric blood flow at the ulcer area were determined. In addition, mucosal biopsy samples were taken from the ulcer area for histological evaluation as well as for the determination of mRNA and protein expression for leptin and constitutive nitric oxide synthase (cNOS) and inducibile nitric oxide synthase (iNOS) by reverse-transcriptase polymerase chain reaction (RT-PCR) and Western blot, respectively. In addition, the gene expression for TGFalpha was analyzed by RT-PCR. Both leptin and CCK reduced significantly the ulcer area as compared to vehicle-treated group by approximately 50%. The treatment with tyrphostin or N(G)-nitro-L-arginine reversed in part the acceleration of ulcer healing by leptin and CCK. The expression of leptin mRNA and protein was significantly increased at the ulcer edge. The leptin-induced acceleration of ulcer healing was associated with increased expression of transcripts for TGFalpha as well as increased mRNA and protein expression for cNOS and iNOS at the ulcer margin. We conclude that leptin accelerates ulcer healing by mechanisms involving the up-regulation of TGFalpha and increased production of nitric oxide due to up-regulation of cNOS and iNOS in the ulcer area.

Topics: Animals; Enzyme Inhibitors; Gastric Mucosa; Gastrointestinal Agents; Leptin; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type III; Nitroarginine; Rats; Rats, Wistar; RNA, Messenger; Sincalide; Stomach Ulcer; Transforming Growth Factor alpha; Tyrphostins

CCK exhibits a potent cytoprotective activity against acute gastric lesions, but its role in ulcer healing has been little examined. In this study we determined whether exogenous CCK or endogenously released CCK by camostate, an inhibitor of luminal proteases, or by the diversion of pancreatico-biliary secretion from the duodenum, could affect ulcer healing. In addition, the effects of antagonism of CCK-A receptors (by loxiglumide, LOX) or CCK-B receptors (by L-365,260), an inhibition of NO-synthase by N(G)-nitro-L-arginine (L-NNA), or sensory denervation by large neurotoxic dose of capsaicin on CCK-induced ulcer healing were examined. Gastric ulcers were produced by serosal application of acetic acid and animals were sacrificed 9 days after ulcer induction. The area of ulcers and blood flow at the ulcer area were determined. Plasma levels of gastrin and CCK and luminal somatostatin were measured by RIA and mucosal biopsy samples were taken for histological evaluation and measurement of DNA synthesis. CCK given s.c. reduced dose dependently the ulcer area; the threshold dose of CCK being 1 nmol/kg and the dose inhibiting this area by 50% being 5 nmol/kg. This healing effect of CCK was accompanied by a significant increase in the GBF at ulcer margin and the rise in luminal NO production, plasma gastrin level and DNA synthesis. Concurrent treatment with LOX, completely abolished the CCK-8-induced acceleration of the ulcer healing and the rise in the GBF at the ulcer margin, whereas L-365,260 remained without any influence. Treatment with camostate or diversion of pancreatic juice that raised plasma CCK level to that observed with administration of CCK-8, also accelerated ulcer healing and this effect was also attenuated by LOX but not by L-365,260. Inhibition of NO-synthase by L-NNA significantly delayed ulcer healing and reversed the CCK-8 induced acceleration of ulcer healing, hyperemia at the ulcer margin and luminal NO release, and these effects were restored by the addition to L-NNA of L-arginine but not D-arginine. Capsaicin denervation attenuated CCK-induced ulcer healing, and the accompanying rise in the GBF at the ulcer margin and decreased plasma gastrin and luminal release of somatostatin when compared to those in rats with intact sensory nerves. Detectable signals for CCK-A and B receptor mRNAs as well as for cNOS mRNA expression were recorded by RT-PCR in the vehicle control gastric mucosa. The expression of CCK-A receptor mRNA and cNOS mRNA wa

Topics: Animals; Cholecystokinin; DNA Replication; Dopamine Agents; Esters; Gabexate; Gastric Mucosa; Gastrins; Guanidines; Hormone Antagonists; Male; Nitric Oxide; Nitric Oxide Synthase; Nitroarginine; Pancreatin; Proglumide; Protease Inhibitors; Rats; Rats, Wistar; Receptors, Cholecystokinin; Regional Blood Flow; RNA, Messenger; Sensory Receptor Cells; Sincalide; Somatostatin; Stomach; Stomach Ulcer

Duodenal fat such as oleate is known to influence gut functions by release of cholecystokinin (CCK), but the contribution of CCK endogenously released by duodenal fat or by diversion of pancreatic juice from the duodenum in the mechanism of mucosal integrity and gastroprotection has been little studied. This study was designed to compare the effect of CCK-8 and intraduodenal (i.d.) instillation of sodium oleate, or diversion of the pancreatic biliary secretions that are known to release CCK, on the gastric mucosal lesions induced by topical application of 100% ethanol or acidified aspirin (ASA) in rats with or without the pretreatment with a CCK-A receptor antagonist, loxiglumide, or with L-365,260 to block CCK-B receptors. In addition, the effect of suppression of prostaglandin (PG) biosynthesis by indomethacin (5 mg/kg i.p.), inhibition of nitric oxide (NO)-synthase by L-NAME (5 mg/kg i.v.), or blockade of sensory nerves by capsaicin (125 mg/kg s.c.) on the protective activity of sodium oleate was determined. Sodium oleate (50-200 mM i.d.), or diversion of pancreatic juice from the duodenum for 3 h that produced significant rise in plasma CCK levels, significantly reduced gastric lesions induced by 100% ethanol to an extent similar to that induced by exogenous CCK-8 (5 nmol/kg s.c.). The protective effect of oleate or diversion of pancreatic juice was accompanied by an increase in gastric blood flow (GBF). Both protection and accompanying hyperemia were completely abolished by blockade of CCK-A receptors with loxiglumide, whereas L-365,260, an antagonist of CCK-B receptors, had no effect. Oleate given i.d. significantly attenuated acidified ASA-induced gastric lesions and gastric secretion while increasing the luminal concentration of somatostatin. These effects were significantly reduced by loxiglumide but not by L-365,260. In contrast, CCK-8, which stimulated gastric acid secretion, failed to affect the lesions induced by acidified ASA and the decrease in the GBF produced by this ulcerogen. Indomethacin, which suppressed PG generation by approximately 90%, failed to influence the protective activity of oleate or CCK-8 against ethanol-induced lesions, whereas L-NAME, vagotomy, or sensory denervation significantly attenuated this protection and accompanying hyperemia. Addition to L-NAME of L-arginine, but not D-arginine, restored the protective and hyperemic effects of CCK-8 and duodenal oleate against gastric lesions induced by ethanol or acidified ASA

Topics: Animals; Capsaicin; Cholecystokinin; Denervation; Dinoprostone; Dopamine Agents; Enzyme Inhibitors; Gastric Acid; Gastric Mucosa; Hormone Antagonists; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Oleic Acid; Pepsin A; Proglumide; Rats; Rats, Wistar; Receptor, Cholecystokinin A; Receptors, Cholecystokinin; Sincalide; Somatostatin; Stomach Ulcer; Vagotomy

Cholecystokinin-8 and pentagastrin protect against ethanol-induced gastric mucosal lesions in rats. The protective effect is antagonized by the nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine. The inhibitory action of NG-nitro-L-arginine is reversed by L-arginine, but not D-arginine. The findings suggest that NO is involved in the gastroprotection induced by both peptides.

Topics: Animals; Anti-Ulcer Agents; Arginine; Ethanol; Gastric Mucosa; Male; Nitric Oxide; Nitroarginine; Pentagastrin; Rats; Rats, Wistar; Sincalide; Stomach Ulcer

We have investigated the effect of intravenous injection of cholecystokinin-8 (CCK-8) and other peptides on gastric lesion formation in response to an intragastric perfusion with 25% ethanol in rats anaesthetized with urethane. 2. Intravenous injection of CCK-8 (50-100 nmol kg-1), but not bombesin (1-100 nmol kg-1), calcitonin gene-related peptide (1-50 nmol kg-1), neurokinin A (1 mumol kg-1) or substance P (100 nmol kg-1), induced protection against gastric haemorrhagic lesions produced by ethanol. 3. The CCKA-antagonist L-364,718 (2.45 mumol kg-1, i.v.) increased the lesion index induced by ethanol and reversed the protective effect of CCK-8 (50 nmol kg-1, i.v.). The CCKB-antagonist L-365,260 (5 mumol kg-1, i.v.) and a lower dose of L-364,718 (0.25 mumol kg-1, i.v.) were ineffective. 4. The gastric protective effects afforded by CCK-8 (50 nmol kg-1, i.v.) were not observed in vagotomized-rats and were reduced by capsaicin pretreatment. In capsaicin-pretreated rats there was a worsening of gastric lesions induced by ethanol-perfusion as compared to those observed in vehicle-pretreated rats. 5. These results demonstrate that the mucosal protective effect of CCK-8 involves, at least in part, the activation of CCKA-receptors and is mediated by vagal capsaicin-sensitive fibres.

Topics: Animals; Benzodiazepinones; Capsaicin; Devazepide; Ethanol; In Vitro Techniques; Male; Neurons; Phenylurea Compounds; Rats; Rats, Inbred Strains; Receptors, Cholecystokinin; Sensory Deprivation; Sincalide; Stomach Ulcer; Vagotomy; Vagus Nerve

Eight dogs underwent gastric total truncal vagotomy and another 8 had gastric superselective vagotomy. Specimens were take from anterior wall of gastric corpus and antrum at weeks after operation for histochemical and electron microscopic observation. The results showed: (1) the sympathetic postganglionic fibers in gastric wall were completely damaged. (2) response of gastric antrum mucosa to CCK-8 and gastric G-17 lowered markedly. (3) the amount of parietal cells increased, the structure of follicular atrophied, the number of mitochondrion in cytoplasm, and the stroma and micrailli on folilculi wall increased. (4) The Campylobacter-like organism (CLO) were found in mucosa of gastric antrum and corpus after operation. The authors discussed the role of gastric sympathetic nerve on gastric secretion and movement, and the relationship between CLO and ulcer recurrence after gastric superselective vagotomy.

Topics: Animals; Dogs; Gastric Mucosa; Histocytochemistry; Microscopy, Electron, Scanning; Parietal Cells, Gastric; Sincalide; Stomach; Stomach Ulcer; Vagotomy, Proximal Gastric; Vagotomy, Truncal