The neurotransmitter GABA (γ-aminobutiric acid) inhibits the activity of signal-receiving neurons by interacting with the GABAA receptor on these cells.1 Binding of GABA to its GABAA receptor results in conformational changes that open a Cl- channel, producing an increase in membrane conductance that results in inhibition of neural activity.nThere are two major types of GABA receptors: the ionotropic GABAA receptors (GABAAR) and the metabotropic GABAB receptors (GABABR). GABAARs belong to the ligand-gated ion channel superfamily.nGABAARs are heteropentamers, in which all five subunits contribute to formation of the pore. Eight subunit isoforms have been cloned: α, β, γ, δ, ε, π, θ, and ρ.1 Six α subunits isoforms (α1-α6) have been shown to exist in mammals.In most cases, the native GABAA receptors consist of 2α, 2β, and 1γ subunits. nThe α3-subunit is highly expressed during development (along with α2 and α5) and then declines in adulthood, where the α1-subunit becomes predominant. The failure to complete this switch could be a major predispositional factor in the development of temporal lobe epilepsy.