Drug and transmitter receptors in human brain. Characterization and localization of serotonin, dopamine and adrenergic receptors

Abstract

The neuroreceptors in the brain are the targets of transmitters and drugs. Tritiated ligands - mostly selective antagonists - allowed to characterize the dopamine, serotonin and adrenergic receptors in human brain. Their properties were compared to those of rat brain receptors. Our results confirm the high affinity of several antagonist drugs for the corresponding binding sites in human brain. D2 dopamine receptors were identified in the striatum. S2 serotonergic receptors were located mainly in the cerebral cortex and their binding properties in solubilized form did not differ from those of the rat brain solubilized receptors. Adrenergic receptors were located either in cortical and subcortical areas. The subregional study indicates that wide variations could occur between adjacent areas of the cortex and between the different cortical layers. The subcellular distribution of several receptors revealed a main synaptosomal localization in human brain in contrast to other species. The S2 serotonergic receptors, the substance P peptide receptors and the benzodiazepine receptors were studied in the brain of Parkinsonian patients. The results were compared with those obtained in other neurological illnesses. A decrease in receptor number often corresponds to neuronal cell loss in degenerative diseases.