A morphologic study of the behavior of biogenic amines in experimental acetic acid gastric ulcer

Morphological observations were made of the behavior of biogenic amines in the gastric wall of rats with acetic acid-induced ulcer. In the normal rat stomach, abundant adrenergic fibers were seen in the adventitia of arteries and arterioles, with frequently distributed mast cells in their environs, in all gastric wall layers. Mast cells had a more frequent distribution in the antral region than in the corpus ventriculi while enterochromaffin-like cells (EC-like cells) were found with greater frequencies in the latter region of gastric wall. Adrenergic fibers were abundant around blood vessels in perilesional area of the gastric wall of rats with acetic acid ulcer. Mast cells, seen more frequently in the antral region as in the normal rats, showed degranulation in these rats. The population of PAS-positive mucous cells reached its peak in 10 days after injection of acetic acid and subsequently declined with healing of the ulcer, thus remarkably concordant with the ulcer index. Local administration of serotonin produced angiospasm in the greater omentum. The finding indicates a possible participation of arteriospasm by adrenergic nerve fibers in the pathogenesis of gastric ulcer. The results of the present study strongly suggest that biogenic amines have bearing as an aggressive factor upon the angiospasm theory of ulcerogenesis.