GABA A (γ-aminobutyric acid-type A) receptors are members of the cysteine-loop family of neurotransmitter-gated ion channels. GABA binding to A-type receptors induces anion-selective ion channel opening. These receptors are the principal fast inhibitory neurotransmitter receptors in the CNS. GABA A receptors are heteropentamer combinations of seven subunit types; α, β, γ, δ, ε, θ, and π. Three subunits, α, β, and γ, have at least three separate gene products in mammals, and typical GABA A receptors have some combination of α, β, and γ subunits.
The rat α6 isoform is a 57 kDa, 434 amino acid (aa), 4 transmembrane protein with two terminal extracellular regions. The ligand-binding region is in the N-terminus (aa 14 - 221). The expression of the α6 subunit is strongly associated with cerebellar granule cells. The α6 subunit has also been linked to alcohol sensitivity, possible due to a point mutation substitution of arginine for a glutamine at amino acid position 81 in the extracellular N-terminus.