Gamma-aminobutyric acid type A receptor (alpha1, alpha2, alpha3, alpha5, gamma2 subunits) (GABAA receptor (alpha1/2/3/5-gamma2))

The gamma-aminobutyric acid type A (GABAA) receptor is a heteropentameric ligand-gated ion channel that serves as the primary mediator of rapid inhibitory synaptic transmission in the vertebrate central nervous system (Sigel & Steinmann, 2012). Receptors composed of alpha1, alpha2, alpha3, or alpha5 subunits in combination with a gamma2 subunit (and typically beta subunits) are distinguished by their high sensitivity to benzodiazepines, which act as positive allosteric modulators at the alpha-gamma interface (Rudolph & Knoflach, 2011). These specific subunit configurations dictate the receptor's physiological role and pharmacological profile: alpha1-containing receptors primarily mediate sedation and amnesia, while alpha2 and alpha3 subtypes are responsible for anxiolytic and muscle-relaxant effects (StatPearls, 2023). Alpha5-containing receptors are predominantly extrasynaptic and play a key role in tonic inhibition and cognitive functions (IUPHAR, 2024). Clinically, these receptors are major targets for treating anxiety, insomnia, and epilepsy, though non-selective modulation is often limited by side effects such as ataxia and the potential for dependence (Olsen & Sieghart, 2008).

Other names

Benzodiazepine-sensitive GABA-A receptorGABA(A) receptorIonotropic GABA receptorGABRGABA-A receptor alpha1/2/3/5-gamma2 complex

Positive allosteric modulation at the benzodiazepine binding site (located at the alpha/gamma subunit interface) which increases the frequency of chloride channel opening in response to GABA binding, leading to enhanced inhibitory postsynaptic potentials.