Effect of centrally administered oxytocin on gastric and duodenal ulcers in rats

AIM: To investigate the effect of centrally administered oxytocin and its receptor antagonist, atosiban, on gastric acid secretion and on experimentally induced gastric and duodenal ulcers. METHODS: The acute gastric nicer models, such as pylorus ligation, indomethacin-induced and ethanol-induced gastric ulcers were used. Chronic gastric ulcers were induced by acetic acid and duodenal ulcers by cysteamine HCl. RESULTS: In pylorus ligated rats, oxytocin (10 mug/kg, icv) showed significant antisecretory and antiulcer activity (P < 0.01). However, it aggravated the ethanol-induced gastric ulcers and did not show any effect on indomethacin-induced gastric ulcers. Oxytocin increased gastric ulcer healing in acetic acid-induced chronic gastric ulcers. The effect of oxytocin was reversed by atosiban (10 mug/kg, icv), a selective oxytocin receptor antagonist. Atosiban when given alone increased gastric acid secretion and ulcer index in pylorus-ligated rats and also aggravated acetic acid-induced. chronic gastric ulcers. It seems the antiulcer activity of oxytocin was due to its anti-secretory effect. CONCLUSION: Centrally administered oxytocin possesses gastric anti-secretory and anti-ulcer activity and oxytocin antagonist, atosiban, is pro-ulcerogenic in rats.