Immunohistochemical studies on distribution of GABAA receptor complex in the rat brain using antibody against purified GABAA receptor complex.

The distribution of the gamma-aminobutyric acid (GABA)A receptor/benzodiazepine receptor/Cl- channel complex in the rat brain was examined immunohistochemically using the specific antibody against purified GABAA receptor complex. The immunization of white albino rabbit with purified GABAA receptor complex resulted in the formation of specific antibody as indicated by the immunoprecipitation test. Immunohistochemical examinations using the antiserum on rat brain slices by the peroxidase-antiperoxidase method revealed the presence of the following immunoreactive sites which coincided with a previous report using antibody against L-glutamic acid decarboxylase; ventromedial nucleus of hypothalamus, red nucleus, globus pallidus, zona compacta and zona reticulata of substantia nigra, layers of Purkinje cells and granular cells of cerebellum, layers III-V of cerebral cortex and stratum radiatum of hippocampus. These results strongly suggest that immunohistochemical application of the antibody against the purified GABAA receptor complex is a useful tool for identifying GABAergic neurons having GABAA receptor complex-mediated synapses.