Gamma-aminobutyric acid type A receptor alpha-5 beta-gamma-2 benzodiazepine site (alpha5-GABA-A-R BZD site)

The Gamma-aminobutyric acid type A (GABA_A) receptor alpha-5 beta-gamma-2 benzodiazepine site is a specific allosteric binding pocket located at the interface of the alpha-5 and gamma-2 subunits of the pentameric GABA_A receptor complex (Sigel & Ernst, 2018, PMID: 29445467). While most GABA_A receptors containing alpha-1, alpha-2, or alpha-3 subunits are widely distributed and mediate phasic inhibition, alpha-5-containing receptors are primarily localized in the hippocampus and prefrontal cortex, where they mediate tonic inhibition (Atack, 2010, PMID: 20533813). This localized expression makes the alpha-5 site a critical target for the modulation of cognitive processes, including learning and memory consolidation (Soh & Lynch, 2015, PMID: 26101558). Drugs acting as negative allosteric modulators (NAMs) or inverse agonists at this site are being developed to treat cognitive impairment in Alzheimer's disease and Down syndrome by reducing excessive inhibitory tone (Braudeau et al., 2011, PMID: 21412328). Conversely, positive allosteric modulators (PAMs) are being explored for their potential to treat mood disorders and schizophrenia by enhancing GABAergic signaling in specific circuits (Prevot et al., 2019, PMID: 30988301). Because of its restricted neuroanatomical distribution, targeting this site offers a therapeutic window to affect cognition or mood without the sedation and motor impairment typically associated with non-selective benzodiazepines (Rudolph & Knoflach, 2011, PMID: 21670730).

Other names

GABRA5-containing GABA-A receptorAlpha-5 subunit-containing GABA-A receptoralpha5beta2gamma2 GABA-A receptorGABRA5

Allosteric modulation of chloride ion conductance through the GABA-A receptor complex upon binding to the interface of alpha-5 and gamma-2 subunits.