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 ulcer 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 microg/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 microg/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.