Gamma-aminobutyric acid type A receptor (alpha1, alpha2, alpha3, or alpha5 subunits with beta and gamma2 subunits) (GABA_A receptor (alpha1/2/3/5-beta-gamma2))

The Gamma-aminobutyric acid type A (GABA_A) receptor is a heteropentameric ligand-gated ion channel that serves as the primary mediator of rapid inhibitory neurotransmission in the mammalian central nervous system (Olsen & Sieghart, 2008, PubMed: 18652731). This specific receptor assembly, characterized by the presence of alpha1, alpha2, alpha3, or alpha5 subunits alongside beta and gamma2 subunits, defines the classic benzodiazepine-sensitive population (Rudolph & Knoflach, 2011, PubMed: 21850036). Upon binding of the endogenous neurotransmitter GABA, the receptor undergoes a conformational change that opens an integral chloride-selective pore, leading to neuronal hyperpolarization and a reduction in excitability (Sigel & Steinmann, 2012, PubMed: 22483294). These receptors are critical therapeutic targets for a variety of conditions, including anxiety, insomnia, and epilepsy, as they possess a distinct allosteric binding site at the interface of the alpha and gamma2 subunits (StatPearls, 2023, "Physiology, GABA Receptor"). Pharmacological agents such as benzodiazepines act as positive allosteric modulators at this site, enhancing the receptor's response to GABA and producing sedative, anxiolytic, and anticonvulsant effects (Rudolph & Knoflach, 2011). The specific alpha-subunit isoform within the pentamer dictates the pharmacological profile; for instance, alpha1 is associated with sedation, while alpha2 and alpha3 mediate anxiolysis (Sigel & Steinmann, 2012).

Other names

Benzodiazepine-sensitive GABA_A receptorGABA(A) receptorIonotropic GABA receptorBZ-GABAARGABA-A receptor complex

Positive allosteric modulation (PAM) at the benzodiazepine binding site (alpha/gamma2 interface) to increase chloride channel opening frequency; Negative allosteric modulation (NAM); Competitive antagonism.