GABA Receptor

GABA receptors are a class of receptors that respond to the neurotransmitter gamma-aminobutyric acid (GABA), the chief inhibitory neurotransmitter in the vertebrate central nervous system. There are two classes of GABA receptors: GABAA and GABAB. GABAA receptors are ligand-gated ion channels (also known as ionotropic receptors), whereas GABAB receptors are G protein-coupled receptors (also known asmetabotropic receptors). It has long been recognized that the fast response of neurons to GABA that is blocked by bicuculline and picrotoxin is due to direct activation of an anion channel. This channel was subsequently termed the GABAA receptor. Fast-responding GABA receptors are members of family of Cys-loop ligand-gated ion channels. A slow response to GABA is mediated by GABAB receptors, originally defined on the basis of pharmacological properties.