The effect of ranitidine on gastric acid secretory response curves to histamine, pentagastrin or bethanechol in the dog with a Heidenhain pouch.

The H2-receptor antagonists ranitidine and cimetidine were tested against gastric secretory dose-response curves to histamine, pentagastrin and bethanechol in the Heidenhain-pouch dog. Histamine-induced gastric secretion was antagonized in a competitive manner by both ranitidine and cimetidine, but ranitidine was approximately 8 times more potent than cimetidine. Pentagastrin -induced secretion was markedly reduced by ranitidine and cimetidine but this antagonism was not competitive in nature. Bethanechol-induced gastric secretion was slightly reduced by both drugs. These findings are discussed in relation to the physiological control of gastric secretion.