The effect of trimipramine, cimetidine, and atropine on gastric secretion

In the present study a comparison was made of the effect of increasing doses of trimipramine (0.05, 0.10, 0.20, 0.40 mg/kg/h), atropine (7, 14, 21, 28 microgram/kg/h), and cimetidine (0.3, 0.6, 1.2, 2.4 mg/kg/h) on the gastric secretion stimulated by 3 microgram/kg/h of histamine dihydrochloride as continuous infusion, each dose step lasting 30 min. In nine healthy individuals it was found that trimipramine had a stimulating effect on the volume and output of acid during one of eight 15-min periods. The largest dose of atropine caused a reduction of the volume and acid output by 68% and 77%, respectively, whereas cimetidine reduced the volume by 74% and the acid output by 89% during the last five 15-min periods, thus having the most pronounced effect. The study may suggest that the healing effect of trimipramine on peptid ulcer is not linked to the effect on submaximal histamine-stimulated secretion and that a different mechanism of action is probably present for the effect of trimipramine, compared with atropine and cimetidine, on the gastric secretion.