Gastric stress ulcer of the rat: relative contribution of the pyloric sphincter, HCO3- bile reflux and mucosal blood flow.

Gastric ulceration has been induced after stress, combining 24 h of fasting and 48 h of restraint in 9 groups of 20 rats with or without a pyloroplasty or a pylorojejunostomy combined with atropine and gastric infusion of NaHCO3 or taurocholic acid. After death or sacrifice at 48 h, ulcer index and blood in the jejunum were determined. Gastric mucosal blood flow was measured semi-continuously by a laser Doppler velocimeter. There were 45% deaths after 48 h of restraint alone, and 70% in the group combining pylorojejunostomy with taurocholic acid. Mortality was lower (p less than or equal to 0.01) pylorojejunostomy alone and more significantly so (p less than or equal to 0.001) when associated with NaHCO3. There was no death when NaHCO3 and atropine were combined with restraint. The mucosal blood flow increased significantly during the first 12 h of restraint in the taurocholic acid group. Both groups with NaHCO3 had mucosal blood flows similar to the controls. Gastric acid and gastric emptying, mucosal ischemia and bile reflux are joint factors inducing gastric stress ulcer. The 100% survival and the low ulcer index after a treatment by atropine and gastric infusion of NaHCO3 suggest that these well-known drugs should be used more frequently.