Radiohistochemical localization of GABA receptors

Abstract

One can localize GABA receptors by light microscopic autoradiographic techniques. The technique involves labeling high affinity, sodium indepenent GABA binding sites with 3H-Muscimol in slide mounted tissue sections. Autoradiograms are generated by the apposition of emulsions-coated cover slips. We observed large variations in the distribution of GABA receptors throughout the brain. Some high density areas included the granule cell layer of the cerebellum, the dorsal lateral geniculate body, most thalamic nuclei, the external plexiform layer of the olfactory bulb and in the inner plexiform layer of the retina. The distribution of the high affinity receptors was not the same as that of suspected GABAergic nerve terminals or as that for benzodiazepine receptors in all areas. In general, this approach is valuable for obtaining information on GABA receptor densities in small regions of brain.