Subtypes and localization of dopamine receptors in human brain

Dopamine receptors in the human brain play an important role in the pathophysiology and treatment of psychosis and movement disorders. Pharmacological and biochemical studies, and more recently gene cloning techniques, have demonstrated that there are multiple receptors for dopamine in the brain. There is confusion in the literature as new subtypes (D3, D4 and D5 receptors) were classified according to unspecified criteria. At present, however, all subtypes of dopamine receptors that have been identified still fit in the traditional D1/D2 dopamine receptor classification scheme. In this article, a more hierarchical system of nomenclature is proposed and our insights into the distribution and localization of the dopamine receptor subtypes in human brain are summarized. Although the current status of the different subtypes of the D1 and D2 receptor families in human brain remains unclear, their discovery has created hope for the development of more efficacious and specific medicines with less side-effects.