Gamma-aminobutyric acid (GABA)-gated ion channels are widely distributed in the mammalian brain and are major mediators of inhibitory synaptic transmission. A typical GABA ion channel has a pentameric structure consisting of 5 protein subunits, often alpha, beta and gamma or delta, combining to form a central ion conducting pore across the cell membrane. In humans there are six genes that encode alpha subunits, three that encode beta, three that encode gamma, and an additional seven genes that encode other subunits whose function is less-well understood than the alpha, beta and gamma subunits. GABA ion channels open and close in response to secretion of GABA from presynaptic terminals. GABAA alpha6 channels are typically comprised of alpha6, beta2 or beta3, and gamma2 subunits and this combination is preferentially expressed in the mammalian cerebellum in granule cells. GABAA alpha6-containing receptors are located synaptically and comprise<5% of="" all="" gabaa="" receptors="" located="" in="" the="" brain.="" these="" receptors="" are="" insensitive="" to="">