GLUTAMATE RECEPTORS IN STRIATUM AND SUBSTANTIA-NIGRA - EFFECTS OF MEDIAL FOREBRAIN-BUNDLE LESIONS

We examined NMDA-sensitive [H-3]glutamate, [H-3]AMPA, [H-3]kainate and metabotropic-sensitive [H-3]glutamate binding sites in neostriatum an d substantia nigra pars reticulata (SNr) in rats after unilateral 6-hy droxydopamine lesions of the medial forebrain bundle. One week after t he lesion, NMDA, AMPA, kainate and metabotropic receptors were decreas ed in the ipsilateral neostriatum, whereas at three months NMDA recept ors were increased while AMPA, kainate and metabotropic receptors were not changed. In the SNr at one week, only AMPA and metabotropic recep tors were significantly decreased whereas three months after the lesio n NMDA, AMPA and kainate binding sites were decreased. The early decre ase of excitatory amino acid receptors in the striatum is likely to re flect degeneration of dopaminergic fibers, suggesting that specific su bpopulations of excitatory amino acid binding sites are located on dop aminergic terminals.