Interaction between acute gastric ulcer and epinephrine-induced mucosal erosions in the rat.

Gastric mucosal erosions were produced in rats by pyloric occlusion and intraperitoneal injection of epinephrine. Gastric ulcer was induced by the application of acetic acid to the anterior wall of the stomach. The gastric lesions were photographed and examined microscopically. 5 h after pyloric occlusion alone, the gastric mucosa looked essentially normal. After pyloric occlusion and injection of epinephrine, superficial mucosal erosions were observed in the major portion of the fundus. The presence of an acute acetic ulcer was found to inhibit partly or completely the development of mucosal erosions usually induced by pyloric occlusion and injection of epinephrine. It is suggested that this might be due to a local release of inflammatory mediators around the ulcer.