Inhibitory effect of cimetidine on gastric acid secretion vagally activated by physiological means in duodenal ulcer patients.

Vagal activation of gastric acid secretion by modified sham feeding in six patients with duodenal ulcer produced a peak acid response amounting to 52% of the peak acid output after pentagastrin stimulation (PAOpg). Cholinergic reflex stimulation of gastric acid secretion by fundic distension in another six patients with duodenal ulcer produced a peak acid response of 45% of PAOpg. Intravenous infusion of cimetidine in a dose of 100 mg/h markedly inhibited the acid sham feeding response by 90-100% and almost abolished the acid response to fundic distension. The results suggest that gastric acid secretion evoked by physiological vagal activation in man is profoundly inhibited by H2-receptor blocking agents.