SPECIAL LECTURE

Amine Receptors in Human Brain-Biochemistry and Alterations in Neuropsychiatric Disorders

Chikako Tanaka, MD Department of Pharmacology, Kobe University School of Medicine, Kobe

Recent development of the biochemistry of neurotransmitter receptors has opened up important areas of studies on receptor phy­siology and pathology. Macromolecules related to synaptic membranes have become suscep­tible to biochemical analysis such as solubiliza­tion, purification and reconstitution. Binding studies have complemented classical pharma­cological approaches in defining new subtypes for amine receptors. The dopamine receptor is classified into two subtypes DI and D2 as­sociated with and without adenylate cyclase, respectively. We found that the binding subunit of DI receptor is 57,000 dalton protein which has a low affinity for both dopamine and haloperidol and is located in postsynaptic membranes of the striatum and the frontal

cortex. On the other hand, the therapeutic antischizophrenic actions and extrapyramidal side effects of neuroleptics appears to involve D2 receptors. In support of this concept it has been observed that there is an increase in density of D2 receptors but no alteration in DI sites in schizophrenic post-mortem brain. Besides these two postsynaptic dopamine receptors, dopamine neurons probably possess autoreceptor defined as D3 which modulates the dopamine release. From these findings it is apparent that the D2 receptor will call more attention in clinic than the D I receptor does.

Key words: Amine receptors, human brain, neuropsychiatric disorders.

Brain & Development, VoI5,.No 2,1983 107