Mapping of GABAA receptor alpha 5 and alpha 6 subunit-like immunoreactivity in rat brain.

The distribution of the alpha 5 and alpha 6 subunits of the GABAA receptor has been mapped in rat brain using affinity-purified antibodies generated against peptide sequences unique to the respective polypeptides. alpha 5 Subunit-like immunoreactivity was of low density but was distributed across several cell groups including cortical interneurones, hippocampal CA3 pyramidal neurones, the anterior thalamic reticular nucleus and cerebellar Purkinje neurones. alpha 6 Subunit-like immunoreactivity was observed in high density in cerebellar granule cells. These patterns are compatible with in situ hybridisation studies and provide a further anatomical substrate for GABAA receptor heterogeneity in the CNS.