THE EFFECT OF IPRONIAZID AND IMIPRAMINE ON THE BLOOD PLATELET 5‐HYDROXYTRYPTAMINE LEVEL IN MAN

Abstract

Observations are reported on the blood platelet 5-hydroxytryptamine content of six patients receiving imipramine, N-(γ-dimethylaminopropyl)-iminodibenzyl hydrochloride. The response was a fall to a level of one-sixth of the original in three weeks, with little change thereafter. This is in sharp contrast to the action of iproniazid which caused a rise of some 200% in the blood platelet 5-hydroxytryptamine level over the same period. Imipramine in a concentration of 1 mg./ml. had no inhibitory action on 5-hydroxytryptophan decarboxylase; 8·0 μg./ml. of imipramine suppressed two-thirds of the in vitro uptake of 5-hydroxytryptamine (2·5 μg./ml.) by normal human platelets.