Stimulation of Gastric Secretion in Man by a Serotonin Antagonist

Summary The administration of the serotonin antagonist, 1-methyl- d -lysergic acid butanolamide bimaleate (UML-491), to peptic ulcer patients produced striking elevations in gastric secretion of hydrochloric acid, both during the basal state and during stimulation with histamine. The prior infusion of the serotonin precursor, 5-hydroxytryptophan, inhibited the stimulatory effect during the basal state. The possibility that endogenous serotonin may have an inhibitory influence on gastric secretory function is considered.