Gamma-aminobutyric acid type A receptor (chloride channel) (GABA₊ receptor)

The **gamma-aminobutyric acid type A receptor (GABA₊ receptor)** is the primary inhibitory ligand-gated ion channel in the mammalian central nervous system, mediating fast synaptic inhibition through the influx of chloride ions when activated by GABA, its endogenous ligand[2][6][7]. It is a pentameric complex formed from various subunit combinations (including α, β, γ, δ, and ρ isoforms) that results in a large array of receptor subtypes, which contribute to functional diversity[1][7]. Upon binding GABA at the α/β subunit interface, the channel undergoes conformational changes that open the central chloride-selective pore, leading to membrane hyperpolarization and inhibition of neuronal firing[1][2][5]. The GABA₊ receptor is the molecular target for a wide range of therapeutic agents, including benzodiazepines, barbiturates, hypnotics, some anesthetics, and convulsant or anti-convulsant drugs[6][7]. Alteration or dysfunction in GABA₊ receptor signaling is implicated in epilepsy, anxiety, insomnia, neurodevelopmental, and other CNS disorders[2][6]. Safety concerns include tolerance, dependence, sedation, and risk of respiratory depression, particularly with drug combinations or overdose.

Other names

GABA-A receptorGABA₊ receptor chloride channelGABA-Cl channelGABA chloride channelIonotropic GABA receptor

Positive allosteric modulation (e.g., benzodiazepines, barbiturates bind and enhance GABA-mediated chloride influx) Negative allosteric modulation (e.g., picrotoxin blocks the channel) Direct agonism (e.g., muscimol mimics GABA) Competitive antagonism (e.g., bicuculline blocks GABA binding)