Biphasic Action of Reserpine and Isocarboxazid on Behavior and Serotonin Metabolism

Abstract

In longitudal studies on psychiatric patients receiving therapeutic doses of reserpine and isocarboxazid, singly or in combination, we observed that the aggravation of psychotic symptoms sometimes occurring during treatment with reserpine was associated with a marked rise in urinary 5-hydroxyindoleacetic acid. Tranquilization was accompanied by a more moderate increase under the influence of reserpine, or by a reduction of 5-hydroxyindoleacetic acid excretion while on monoamineoxidase inhibitor medication. It is concluded that a moderate rise of free serotonin in the brain is associated with tranquilization, while a greater increase is accompanied by excitation.

Some Aspects of Central Nervous Pharmacology

“…(33) conclude from studies with reserpine and isocarboxazid that a moderate rise in brain serotonin is associated with tranquilization, a larger increase with excitation.…”

Human pharmacology of tranquilizing drugs

“…Rats were also given the drug orally and intraperitoneally. Fifteen minutes after injection, 50 per cent of the blood radioactivity was due to metabolically altered drug. No unchanged promazine was found in the blood after 24 hours.…”