According to their different pharmacological characteristics, GABA receptors can be divided into three types: GABA-A, GABA-B and GABA-C receptors. GABA-A receptor/channel can be blocked by bicuculline; Baclofen can activate GABA-B receptor. However, GABA-C receptor/channel is insensitive to bicuculline and baclofen.
Both GABA-A and GABA-C receptors can form ligand-gated chloride channels, while GABA-B receptor belongs to G protein-coupled receptor family and has K+ and Ca2+ channels.
GABA-A receptor is the main inhibitory receptor in the central nervous system, and barbiturates and benzodiazepines act on GABA-A receptor, exerting its pharmacological effects such as sedation, hypnosis and anticonvulsant.