Antipsychotic Drugs, Dopamine D2 Receptors, and Schizophrenia

I. Introduction .............................................................................................................................43 II. Do the Clinical Potencies of Antipsychotics Correlate with the Dissociation Constants at D2? ......................................................................................................................................44 III. Do Therapeutic Concentrations of Antipsychotics Occupy the Same Levels of Brain D2 Receptors?...............................................................................................................44 IV. Does Endogenous Dopamine Raise the Antipsychotic Concentration Needed for D2 Block? ...............................................................................................................................49 V. What is the Basis for the Apparently Low D2 Occupancy by Clozapine and Quetiapine?..............................................................................................................................50 VI. What is the Receptor Basis of Antipsychotic Drugs which Elicit Little or No Parkinsonism? ...................................................................................................................52 VII. Does Blockade of Serotonin Receptors Alleviate Parkinsonism? .........................................53 VIII. Clinical Implications ...............................................................................................................54