THE role of dopamine in the subthalamic nucleus to control motor behaviour was investigated in rats using bilateral microinfusions of the dopamine D1receptor antagonist SCH23390 and the dopamine D2receptor antagonist S(-)-sulpiride. Selective blockade of subthalamic D1receptors, but not of D2receptors, produced catalepsy. These findings suggest that dopamine D1receptors within the subthalmic nucleus play a prominent role in the regulation of motor functions. Furthermore, the data point to the possibility that a reduced dopaminergic tone at subthalamic dopamine D1receptors might contribute to akinesia in Parkinson's disease.