CHARACTERIZATION OF DOPAMINE-RECEPTOR BINDING-SITES IN THE SUBTHALAMIC NUCLEUS

EXPERIMENTS were undertaken to determine the distribution and binding profile of dopamine (DA) receptors within a key extra-striatal region of the rat basal ganglia, the subthalamic nucleus (STh). Analysis of [I-125]NCQ-298 autoradiograms showed that binding sites of the D-2-receptor family are abundant in the STh. Competition studies indicated that these sites were specifically of the D-2 subtype. However, contrary to previously published data, [I-125]SCH-23982 autoradiograms failed to reveal D-1 receptor binding in the STh. These data suggest that DA acting at D-2 receptors may directly modulate STh neural activity and furthermore that the antagonism of STh D-2 receptor binding by neuroleptics may be involved in the expression of extrapyramidal motor disturbances.