Excitatory amino acid receptor regulation after subthalamic nucleus lesions in the rat.

The subthalamic nucleus plays a pivotal role in the regulation of basal ganglia output. Recent electrophysiologic, lesion and immunocytochemical studies suggest that the subthalamic nucleus uses an excitatory amino acid as a neurotransmitter. After complete ablation of the subthalamic nucleus, we have examined the NMDA, AMPA, kainate and metabotropic subtypes of excitatory amino acid receptors in two major subthalamic projection areas (globus pallidus and substantia nigra pars reticulata) with quantitative autoradiography. Two weeks after ablation, binding sites for [3H]AMPA and [3H]kainate increased in substantia nigra pars reticulata ipsilateral to the lesion. In globus pallidus on the lesioned side, [3H]glutamate binding to the NMDA recognition site decreased. The results suggest that glutamate receptors regulate after interruption of subthalamic nucleus output.