Effect of cimetidine on net ion fluxes across the rat gastric mucosa during mucosal damage after gastric ischemia and after intravenous acetylsalicylic acid.

This study was performed to determine the relationship between net ion fluxes across the rat gastric mucosa and gastric mucosal damage after gastric ischemia and after intravenous administration of acetylsalicylic acid, and to determine the effect of cimetidine on these parameters. Gastric mucosal blood, albumin, and fluid loss that occurred after gastric ischemia was not associated with an increase in net H+ flux from mucosa to serosa. A significant increase in net Na+ and K+ flux from serosa to mucosa occurred. In the presence of cimetidine (150 mg/kg X h, i.v.), which reduced gastric damage, net H+ flux increased significantly, whereas there was an inhibition of Na+ and K+ fluxes. Acetylsalicylic acid-induced gastric hemorrhage preceded an increase in net H+ flux from serosa to mucosa, although net Na+ and K+ fluxes were unaffected. Cimetidine (150 mg/kg X h, i.v.) potentiated gastric hemorrhage and this was associated with an increase in net K+ flux from serosa to mucosa. These studies demonstrate that overt damage to the rat gastric mucosa can occur without changes in net ion fluxes across the gastric mucosa.