Localization of L-glutamate and L-aspartate synaptic receptors in chick retinal neurons

Kainic acid (KA) produces lesions in the chick retina when injected intravitreally. In order to ascribe L-glutamate and L-aspartate receptors to specific neuronal populations, we measured L-[3H]glutamate and L-[3H]aspartate specific binding to membranes from retinas treated with different doses of KA. A 20% reduction in glutamate and aspartate receptors was observed when amacrine cells were eliminated (50 nmol KA). When 120 nmol KA were injected, horizontal cells were highly decreased and so were glutamate (48%) and aspartate (22%) receptors. 200 nmol KA killed most of the bipolar cells in addition to the horizontal and amacrine cells; this lesion was associated with an additional 21% decrease in the specific binding of aspartate but not glutamate. Receptors for both compounds which remained after 200 nmol KA (30%) could be located in ganglion cells, which were spared by KA.