Prevention of stress-induced gastric ulcers by mu- and delta-opioid agonists in the rat.

The effects of intraperitoneal and intracerebroventricular administration of mu- and delta- selective opioid receptor agonists (DAGO and DPDPE, respectively) on gastric lesions, were investigated in cold-restraint-stressed rats. DAGO and DPDPE, peripherally and centrally administered, induced a significant gastric protection. Naloxone prevented the effects of both opioids whereas naltrindole prevented the gastric protection induced by DPDPE but not that by DAGO. The results suggest that mu- and delta-opioid agonists prevent gastric damage induced by stress through an involvement of both central and peripheral mu- and delta-opioid receptor subtypes.