Abstract
1 Investigations were carried out on the antagonism of the action of carbamylcholine chloride on the isolated fundus of the rat stomach by several tricyclic antidepressants. 2 The anticholinergic potency of the compounds was in the order: GP 45437>amitriptyline>protriptyline>desmethylimipramine>opipramol. All of the antagonists were less effective than atropine. 3 Statistical analysis was carried out to determine whether the theory of competitive antagonism would fit the data obtained.