3H-spiroperidol binding in human temporal cortex (Brodmann areas 41-42) occurs at multiple high affinity states with serotonergic selectivity.

Abstract

3H-Spiroperidol labels multiple high affinity states with serotonergic selectivity in human prefrontal cortex and with dopaminergic selectivity in human caudate and putamen. The characteristics of the binding of this ligand in human temporal cortex have not been previously described. Brodmann areas 41-42 in the temporal cortex are associated with primary auditory sensation and, in epileptics, with auditory hallucinatory experiences. We found that in this region of the human brain, antipsychotic ligands bind at multiple high affinity states, the majority of which exhibit serotonergic, rather than dopaminergic, selectivity. Dose-response data is best resolved by a three-site fit. Results of the co-analysis of dose-response data with saturation data indicates that two of the 3H-spiroperidol affinity states may represent the high and low affinity states of the serotonin (5HT)2 receptor, while a third affinity state may represent the 5-HT1A receptor.