Protective effect of propranolol on ethanol-induced gastric lesions in mice

The non-selective beta-adrenoceptor antagonist, propranolol, has a protective effect on ethanol-induced gastric haemorrhagic lesions in mice when given in doses of 2.5, 5.0 and 10 mg/kg either parenterally (i.p.) or orally. The effect was more marked after oral administration. Another non-selective beta-adrenoceptor antagonist, timolol, failed to protect against ethanol-induced gastric lesions. Thus, beta-adrenoceptor blockade does not seem to play a role in the gastroprotective effect of propranolol. Pretreatment with the cyclo-oxygenase inhibitor, indomethacin, abolished the protective effect of 2.5 and 5.0 mg/kg i.p. propranolol but only attenuated the effect of the higher i.p. dose (10 mg/kg) and the three oral doses. These results indicate that the gastroprotective effect of propranolol is mediated partly by the prostaglandin pathway and partly by another mechanism which, we suggest, may involve its membrane-stabilising action.