Implications of gastric topical bioactive peptides in ammonia-induced acute gastric mucosal lesions in rats

Background: Ammonia, one of the pathogenic factors in Helicobacter pylori-induced mucosal injury, induces acute mucosal lesions in the rat glandular stomach. Methods: The effect of ammonia administered intragastrically on gastric peptides was investigated in urethane-anesthetized rats. Results: Gastric mucosal lesions were observed 5 min after 0.3% ammonia (4 ml/kg, intragastrically). Immunoreactive endothelin-1 (ET-1) and immunoreactive thyrotropin-releasing hormone (TRH) concentrations in the gastric wall decreased significantly 2 min and 5 min after ammonia, respectively. A significant increase in gastric juice immunoreactive ET-1 and TRH levels was reciprocally observed. The severity of gastric mucosal injury and changes in gastric immunoreactive ET-1 and TRH concentrations were shown to be concentration-dependent 30 min after ammonia. Atropine (5 mg/kg, intraperitoneally, -20 min) prevented ammonia-induced injury accompanied by a block of changes in gastric immunorective ET-1 and TRH concentrations. ...