An abnormal increase in the activity of neurons of the subthalamic nucleus is a key pathophysiological feature of Parkinson's disease. We sought to determine whether riluzole, a sodium channel inhibitor that interferes with glutamatergic neurotransmission, affects neuronal activity in this brain region. Intravenous administration of riluzole reduced the discharge rate of subthalamic neurons in rats with 6-OHDA-induced lesions of the midbrain. By contrast, no effect was observed in nonlesioned control animals. This property may contribute to the neuroprotective effects of riluzole in animal models of PD through the modulation of the glutamatergic inputs these neurons feedback to nigral dopaminergic neurons. © 2001 Movement Disorder Society.