The effect of SC-15396, atropine and mepyramine on gastrin-, bethanechol- and histamine-stimulated gastric acid secretion in rats and guinea-pigs

The effect of SC-15396 (“antigastrin”; 2-phenyl-2-(2-pyridyl)thioacetamide), atropine and mepyramine on gastrin-, bethanechol- and histamine-stimulated gastric acid secretion was studied in rats and guinea-pigs. For all three stimulants parallel dose response curves were obtained except in guinea-pigs where bethanechol even in very high doses displays a poor activity in stimulating gastric acid secretion. The maximal secretory response was found to be 12·7 ± 5·0 μ-equiv HCl/10 min in rats and 53·2 ± 27£9 μ-equiv HCl/10 min in guinea-pigs. All stimulating effects on gastric acid secretion were reduced by SC-15396; atropine abolished the secretory responses to bethanechol. Mepyramine was ineffective. In accordance with these findings the mechanism of action of gastrin and a receptor model on the oxyntic cell are discussed.