Neuroprotective effect of chronic inactivation of the subthalamic nucleus in a rat model of Parkinson's disease.

Several evidences showed that glutamate can be implicated in the degenerative process of dopaminergic neurons in Parkinson's disease. The treatment with NMDA antagonists have been shown to induce a neuroprotective effect in animal models of this disease. As subthalamic nucleus neurons send direct glutamatergic projections to the substantia nigra, we studied the effects of kainic acid lesion of this nucleus on the degeneration of dopaminergic neurons induced by microinjection of 6-hydroxydopamine in the striatum of rat done one week after the first lesion. Animals were killed 15 days after the injection of 6-hydroxydopamine. Immunohistochemical study showed that lesion of the subthalamic nucleus can prevent the degeneration of substantia nigra dopaminergic somata when carried out one week prior to 6-hydroxydopamine injection in the striatum. Nevertheless neurochemical results showed that this lesion did not antagonize the striatal 6-hydroxydopamine-induced dopamine depletion in the striatum 15 days after 6-hydroxydopamine injection.