[3H]SCH 23390 labels dopamine D-1 receptor sites in the rat kidney

The binding of [3H]SCH 23390, a selective dopamine D-1 receptor radioligand, to rat kidney cortical membranes was studied. Scatchard analysis revealed a single class of binding sites. Of dopamine, noradrenaline and serotonin, dopamine was the most potent of these to displace [3H]SCH 23390 binding. The selective D-1 ligands SCH 23390 and SK & F 38393 were more potent to displace [3H]SCH 23390 than the selective D-2 ligands S-sulpiride and LY 171555, thus indicating that [3H]SCH 23390 binds predominantly to dopamine D-1 receptor sites.