Consequences of the Evolution of the GABAA Receptor Gene Family

1. This paper reviews the evolution of the family of genes present in mammals and other vertebrates that encode γ-aminobutyric acid (GABA) type A (GABAA) receptors, which are the major inhibitory neurotransmitter receptors in the central nervous system (CNS). In mammals, 16 different polypeptides (α1–α6, β1–β3, γ1–γ3, δ, ε, π, and θ) have been identified, using recombinant DNA techniques, each of which is encoded by a distinct gene. The products of these genes assemble in diverse combinations to form a variety of receptor subtypes that have different sensitivities to a number of clinically relevant compounds, such as the benzodiazepines (BZs).