The induction of gastric mucosal tolerance to alcohol by chronic administration.

Acute alcohol intake produces marked damage to gastric mucosa. Whether gastric mucosa develops tolerance to repeated alcohol administration is unknown. To test this, we compared the effects of acute and chronic alcohol administration in male rats. Thirty-one Sprague-Dawley rats maintained on Chow diet received the following: group A, water for 4 weeks; group B, 50% EtOH for 4 weeks; group C, water for 4 weeks, then 8 hr prior to sacrifice 50% EtOH; group D, 50% EtOH for 4 weeks, then alcohol 8 hr prior to sacrifice. Control animals did not show macroscopic or microscopic changes in fundic or pyloric mucosa. The percentage fundic mucosa showing lesions (49%) in the acute EtOH group (group C) was significantly greater than in control (0%), chronic EtOH group (group B, 8%), and chronic plus acute EtOH (group D, 14%). Pyloric lesions were not significantly diferent between treatment groups C (9%), B (4%), and D (8%). Histologic changes in group C (acute alcohol) consisted of superficial erosions accompanied by severe hemorrhagic changes in the upper part of the gastric mucosa. In group B (chronic alcohol) and group D (chronic + acute alcohol) changes consisted of small superficial erosions without hemorrhagic changes. Our study shows that damage in rat gastrc fundic mucosa following acute intragastric administration of EtOH is significantly less in rats receiving EtOH chronically than in rats receiving only acute EtOH. We conclude that rat gastric mucosa is capable of developing tolerance to repeated administration of 50% alcohol.