Localization of striatal excitatory amino acid binding site subtypes to striatonigral projection neurons

Quantitative autoradiography was used to examine the cellular localization of excitatory amino acid binding sites in the striatum following selective lesion of striatonigral projection neurons. Degeneration of striatonigral neurons was induced unilaterally by injection of the suicide transport toxin, volkensin, into the left substantia nigra. Twelve days following nigral volkensin injection there was a reduction of all excitatory amino acid binding site subtypes in the striatum ipsilateral to the injected nigra. The reduction in N-methyl-D-aspartate (NMDA) binding sites was significantly greater than the loss of D,L-alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA), kainate and metabotropic binding. These results indicate that there are NMDA, AMPA, metabotropic and kainate binding sites on striatonigral projection neurons and suggest that the NMDA subtype may be selectively enriched on striatonigral neurons.