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

AIM: To investigate the effect of centrally administered oxytocin and its r eceptor antagonist, atosiban, on gastric acid secretion and on experimental ly induced gastric and duodenal ulcers. METHODS: The acute gastric nicer mo dels, such as pylorus ligation, indomethacin-induced and ethanol-induced ga stric ulcers were used. Chronic gastric ulcers were induced by acetic acid and duodenal ulcers by cysteamine HCl. RESULTS: In pylorus ligated rats, ox ytocin (10 mug/kg, icv) showed significant antisecretory and antiulcer acti vity (P < 0.01). However, it aggravated the ethanol-induced gastric ulcers and did not show any effect on indomethacin-induced gastric ulcers. Oxytoci n increased gastric ulcer healing in acetic acid-induced chronic gastric ul cers. The effect of oxytocin was reversed by atosiban (10 mug/kg, icv), a s elective oxytocin receptor antagonist. Atosiban when given alone increased gastric acid secretion and ulcer index in pylorus-ligated rats and also agg ravated acetic acid-induced. chronic gastric ulcers. It seems the antiulcer activity of oxytocin was due to its anti-secretory effect. CONCLUSION: Cen trally administered oxytocin possesses gastric anti-secretory and anti-ulce r activity and oxytocin antagonist, atosiban, is pro-ulcerogenic in rats.