Protective effect of propranolol on ethanol-induced gastric lesions in rats: probable mechanism of action.

ABSTRACT

The non-selective beta-adrenoceptor antagonist, propranolol, has been reported to protect against gastric injury in mice, an effect only partly due to prostaglandin release. This study was designed to confirm the gastric cytoprotective effect of propranolol in another species of animal, the rat, and investigate further its mechanism of action. Our results show that propranolol prevents both ethanol-induced gastric lesions as well as ethanol-induced contraction of the circular muscle of rat fundic strip. The local anaesthetic, lignocaine also inhibited the effect of ethanol on circular muscle. However, timolol, another non-selective beta-adrenoceptor antagonist, failed to produce such an action. The effect of propranolol was abolished by the cyclooxygenase inhibitor, indomethacin and a high dose of the guanylate cyclase inhibitor, methylene blue. The results suggest that in addition to prostaglandins, endogenous nitric oxide and the membrane stabilising action of propranolol may also be involved in its gastroprotective action.