High affinity serotonin binding sites in human brain: a comparison of cerebral cortex and basal ganglia

Abstract

The high-affinity binding of³H-serotonin and³H-DP-AT was studied in membrane preparations and tissue sections of cerebral cortex and basal ganglia of human brain. In tissue sections,³H-serotonin bound to sites present at high density in the cerebral cortex, hippocampus and basal ganglia.³HDPAT bound predominantly to the outer layers of the cerebral cortex and the hippocampus, no significant binding was observed in the basal ganglia. In cortical membranes³H-serotonin bound to a heterogeneous population of sites, one of which was similar to a binding site labelled by³H-DPAT (the putative 5HT-1A receptor).³H-serotonin binding to membranes prepared from the putamen displayed low affinity for DPAT, mesulergine and spiperone, RU 24969 was considerably less potent than serotonin itself. This³H-serotonin binding site does not have the properties of those sites described in rodent brain (5 HT-1 A, 5 HT-1 B, and 5 HT-1 C), and may represent a novel serotoninergic binding site.