LOCALIZATION AND GENE-EXPRESSION OF SEROTONIN 1A(5HT(1A)) RECEPTORS IN HUMAN BRAIN POSTMORTEM

We investigated the binding parameters, i.e. the maximum binding capac ity (B-max) and the dissociation constant (K-d), of [H-3]8-hydroxy-2-( di-N-propylamino)tetralin ([H-3]8-OH-DPAT) labeling the serotonin rece ptor of the 1A type (5HT(1A)), and the distribution of the mRNA encodi ng it in some human brain areas obtained from autoptic samples. The re sults showed that the B-max was significantly higher in the hippocampu s than in the prefrontal cortex and the striatum, while the K-d had th e inverse, although not significant, pattern. The expression study rev ealed that 5HT(1A) mRNA distribution in the hippocampus and prefrontal cortex was consistent with the data of the [H-3]8-OH-DPAT binding. A different result was obtained in the striatum where no 5HT(1A) mRNA ex pression was detected, despite the measurement of specific [H-3]8-OH-D PAT binding. These findings underline the different nature of [H-3]8-O H-DPAT binding sites in different brain areas and the need for further studies on 5HT receptor gene expression in human brain.