DIFFERENTIAL VISUALIZATION OF DOPAMINE-D(2) AND DOPAMINE-D(3) RECEPTORS IN RAT-BRAIN

The mRNA for the dopamine D3 receptor is confined to limbic regions an d the D3 receptor may be a target for antipsychotic medications. We us ed quinpirole and domperidone to try to visualize D3 and dopamine D2 r eceptors selectively in rat brain, using in vitro autoradiography and digital subtraction. We used I-125-sulpiride, a ligand with high affin ity for the D2 receptor in brain and for the D3 and D2 receptors in tr ansfected cells. Our data indicate that the D2 receptor is present in much greater density than the D3 receptor in rat brain, even in limbic regions.