Restraint-induced stress ulcer. II. biochemical and ultrastructural studies of gastric mucosa

The aim of these studies was to evaluate the light and electron microscopic changes of the gastric mucosa of restrained rats, and to determine if there were correlations between structural changes, histidine decarboxylase activity, histamine content, and gastric secretion. In areas with high-grade mucosal lesions, signs of functional hyperactivity of the oxyntic and chief cells and cytoplasmic degranulation of the enterochromaffin-like cells were observed. These changes were not influenced by vagotomy. The hyperactivity of the chief cells was related to a higher proteolytic activity of the gastric juice and to an increased excretion of uropepsinogen (p<0.01). The hyperactivity of the oxyntic cells was not accompanied by an increase in total acidity, which could be explained by hydrogen ion back-diffusion through a damaged gastric mucosal barrier. The increase in histidine decarboxylase activity (p<0.01) and the decrease of histamine content (p<0.01) in the glandular mucosa of restrained rats, together with the microscopic and ultrastructural observations, suggest that the early microcirculatory changes are due to local alterations in the metabolism of vasoactive amines. © 1980 Société Internationale de Chirurgie.