DOPAMINE-RECEPTOR PHARMACOLOGY

Dopamine receptors are the primary targets in the treatment of schizophrenia, Parkinson's disease, and Huntington's chorea, and are discussed in this review by Philip Seaman and Hubert Van Tol. Improved therapy may be obtained by drugs that selectively target a particular subtype of dopamine receptor. Most antipsychotic drugs block D-2 receptors in direct correlation to clinical potency, except clozapine, which prefers D-4 receptors. D-1 and D-2 receptors can enhance each other's actions, possibly through subunits of the G proteins. In schizophrenia, the D-2 and D-3 receptor density is elevated by 10%, while the D-4 receptor density is elevated by 600%. Therefore, D-4 receptors may be a target for future antipsychotic drugs. While antipsychotics originally helped to discover dopamine receptors, the five cloned dopamine receptors are now facilitating the discovery of selective antipsychotic and antiparkinson drugs.