Gastric mucosal protection by chronic restraint: effects of vagotomy.

This study was performed to determine the effects of vagotomy on the gastric mucosal resistance to ethanol injury that develops in the rat in response to prolonged mild restraint. The resistance to ethanol injury up to 4 days after cessation of chronic mild restraint (CMR) was also examined. Intragastric administration of ethanol/acid to rats previously subjected to 10 days of CMR produced significantly (P less than 0.0001) less damage than to the mucosae of control rats. While previous exposure to CMR appeared to prevent the necrotic gastric damage induced by ethanol, damage to the surface epithelium was not prevented. When similar experiments were performed on CMR and control rats that had truncal vagotomy, the extent of ethanol/acid injury in the two groups was not significantly different. Intragastric administration of ethanol/acid to 8-day CMR rats produced 91% less (P less than 0.005) gastric damage than in control rats. When ethanol was administered 2 days after cessation of CMR, the gastric injury was still significantly less (P less than 0.01) than in control rats. However, when ethanol was administered 4 days after cessation of CMR, the resulting damage was not significantly different from that of control mucosae. These studies suggest that intact vagal innervation may be necessary for adaptation of the gastric mucosa to chronic mild restraint. These adaptive changes are still present up to 4 days after cessation of the restraint procedure.