Effect of prostaglandin E2, cimetidine, and atropine on ethanol-induced gastric mucosal damage in the rat.

The effect of prostaglandin E2 (PGE2), cimetidine, and atropine on ethanol-induced gastric mucosal damage was studied in anaesthetised rats. Intravenous infusion of PGE2 (120 micrograms/kg X h) protected the gastric mucosa against lesions produced by irrigation of the stomach with 30% (v/v) ethanol in 100 mM HCl plus 50 mM NaCl. PGE2 had no effect on back-diffusion of H+ ions, whereas outflow of Na+ and K+ ions decreased. The increases in pepsinogen secretion and gastric mucosal blood flow during mucosal damage were not affected by PGE2. Cimetidine (25 mg/kg intravenously) failed to prevent mucosal haemorrhages induced by ethanol. Cimetidine caused a slight decrease in outflow of Na+ ions but otherwise had no effect on the variables measured. Atropine sulphate (1 mg/kg X h intravenously) similarly did not protect the gastric mucosa against ethanol-induced lesions, nor did it change ion fluxes, fluid output, or pepsinogen secretion during mucosal damage. Gastric mucosal blood flow, however, was lower in the atropine-treated rats than in the control rats. The results indicate that PGE2, but not cimetidine or atropine, protects the gastric mucosa against ethanol-induced damage in anaesthetised rats, but that this effect is not due to prevention of back-diffusion of H+ ions or to increased mucosal blood flow.