Experimental studies on developmental mechanism of histamine induced ulcers and ulcer inhibitory effects of histamine receptor antagonists.

Study was made of the developmental mechanism of histamine induced ulcers and inhibitory effects of receptor antagonists from the view point of gastric acidity and microvasculature of the gastric mucosa, and the following results were obtained. 1. In histamine induced ulcers, hypersecretion of gastric acid caused by histamine is not the primary developmental mechanism of the lesion. The main cause is considered to be disturbance of microcirculation in the gastric mucosa attributable to the effects of histamine on the microvasculature of the mucosa. 2. Of the histamine receptor antagonists, diphenhydramine, an Hi-antagonist, was unable to inhibit hypersecretion of gastric acid and disturbance of microcirculation of the gastric mucosa caused by histamine, and thus could not suppress the development of histamine induced ulcers, but cimetidine, an H 2-antagonist, inhibited not only hypersecretion of gastric acid, but also prevent disturbance of microcirculation in the mucosa, and consequently suppressed histamine induced ulcers. 311