Effects of water-immersion stress on gastric secretion and mucosal blood flow in rats

The correlation between acid secretion and mucosal blood flow in the rat stomach during stress loading was determined to provide clues to the etiology of the gastric ulceration which thus occurs. The gastric acid output was increased remarkably by water-immersion stress at 23 degrees C, and this increase lasted while the stress was given, yet the mucosal blood flow did not show a corresponding increase. In rats stressed for 3 hr, ulcerative changes were observed in the glandular portion of the stomach. The stress-induced increase in acid output correlated well with the severity of erosions. Pretreatment of animals with atropine 10 microgram/kg, given subcutaneously, or vagotomy, inhibited the increase in acid output and also inhibited the ulcer formation caused by the stress: however, the mucosal blood flow in these animals decreased significantly. These results suggest that when there is an elevation of gastric acid secretion with no parallel increase in mucosal blood flow, gastric ulceration may occur under conditions of stress.