An evaluation of the influence of increased gastric acid in the aetiology of reserpine-induced ulcers in rat stomachs

Abstract

Summary Reserpine (5 mg/kg), injected i.p. 4 h before sacrifice, produced mucosal ulcers in both the rumenal and glandular portions of pylorus-occluded rat stomachs. These effects were accompanied by increased gastric acid and secretory volume, stomach wall mast cell degranulation, and increased microcirculatory blood volumes in the superficial third of the glandular mucosa. Concomitant neutralisation of gastric acid with sodium bicarbonate (100 mg), given by intragastric tube immediately after pylorus occlusion and before reserpine injection, markedly prevented rumenal but not glandular ulcer formation. Gastric acid neutralisation did not affect mast cell degranulation or the mucosal microcirculatory changes produced by the drug. These findings suggest that the microcirculatory changes are more likely to result directly from mast cell degranulation, rather than indirectly from the action of increased luminal acid. They also provide more evidence to indicate that reserpine-induced rumenal ulceration depends chiefly on the presence of luminal gastric acid, whereas glandular ulcer formation could be mainly the consequence of mucosal vascular dilatation and congestive ischaemia produced by gastric mast cell histamine release.