Defensive Mechanism in Peptic Ulcer and Assessment of Anti-ulcer Agents

ABSTRACT Defensive mechanism of gastric mucosa was studied. (1) In guinea pig gastric mucosa in vitro, reduction in ATP content occurred preceeding the back diffusion of mucosal acid induced by aspirin or taurocholate. (2) The hydrogen ion permeability increases before the increase in activated pepsin in rat gastric mucosa with aspirin-induced ulceration. (3) Increase in the hydrogen ion permeability was specific for the presence of erosions and intestinal metaplasia in gastric ulcer patients. (4) Anti-ulcer agents showed different patterns in inhibiting the events leading to aspirin-induced ulceration in rats. From these findings, it has been concluded that the increase in hydrogen ion permeability is the consequence of cellular damage in the gastric mucosa and to cause erosions which forms the background for ulceration.