Receptors that respond to the GABA neurotransmitter

The GABA receptors are a class of receptors that respond to the neurotransmitter gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system. There are two classes of GABA receptors: GABA-A and GABA-B. GABA-A receptors are ligand-gated ion channels, whereas GABA-B receptors are G protein-coupled receptors (also known as metabotropic receptors).

It has long been recognized that the fast response of neurons to the transmitter GABA is due to direct activation of an anion channel. This channel was subsequently termed the GABA-A receptor. Fast-responding GABA receptors are members of family of Cys-loop ligand-gated ion channels.

In ionotropic GABA-A receptors, binding of GABA molecules to their binding sites in the extracellular part of receptor triggers opening of a chloride ion-selective pore. The resulting chloride ion flux inhibites the firing of new action potentials (it silences neurons).