“…The GABA A R system is highly conserved in mammals, but some quantitative and/or qualitative differences have been found between human and rat in brain regional expression patterns of the subunits. The expression of some subunits is very restricted; e.g., the expression of ␣6 subunit is confined to cerebellar granule cells (Hadingham et al, 1996), whereas ␣1 is widely expressed in most brain regions (Houser et al, 1988;Akbarian et al, 1995;Loup et al, 2006;Waldvogel et al, 2008;Fatemi et al, 2009). Some cell types express only a small repertoire of subunit mRNAs (e.g., ␣1, 2, 3 and ␥2 in cerebellar Purkinje cells) (Wisden et al, 1992), whereas the majority of individual human dentate granule neurons express 10 or more different subunit mRNAs (Brooks-Kayal et al, 1999).…”