Synaptic localization of striatal NMDA, quisqualate and kainate receptors

Striatal binding of labeled glutamate to N-methyl-D-aspartate (NMDA) receptors, D,L-alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid (AMPA) to quisqualate receptors and kainate to kainate receptors was examined in rats which had received unilateral decortications or unilateral striatal quinolinic acid lesions. One week after decortication, there were no significant changes in NMDA, quisqualate or kainate receptors in the striatum ipsilateral to the lesion, when compared to the striatum contralateral to the lesion. In contrast, binding to NMDA receptors was reduced by 92%, to quisqualate receptors by 80% and to kainate receptors by 81% in striatum 3 months after quinolinic acid lesions. The reduction in NMDA receptor binding was significantly greater than the loss of quisqualate or kainate receptors. These results suggest that NMDA, quisqualate and kainate receptor recognition sites are located postsynaptically in the striatum. These results also have implications for the quinolinic acid model of Huntington's disease.