STUDIES OF THE 5-HYDROXYTRYPTAMINE (SEROTONIN) CONTENT IN HUMAN BRAIN1

Abstract

The presence of serotonin in human brain structures has been demon- strated. The areas of the allocortex had higher serotonin concentrations than the isocortex. The highest concentration of serotonin per unit weight of tissue is in the mesencephalic structures (mainly substantia nigra and probably red nucleus); the diencephalic structures (hypotha-lamus) contain also relatively large amounts of this neurohormone. The cerebellum as well as the isocortex have the lowest concentrations of serotonin.