The frequent co-localization of α, β, and γ, or α4/α6,β, and δ subunits in the brain and in synaptic or extrasynaptic sites of specific neurons, respectively, the evidence that these subunits could be co-precipitated from brain membrane extracts, that they form defined recombinant receptors with a specific pharmacology, their identification by receptor binding and electrophysiological studies and the identification of their function using molecular-genetic knock-in or knock-out and pharmacological experiments, suggest the actual existence of 8 different GABAA-R subtypes (α1-6βγ2, α4βδ / α6βδ).
