Gamma-aminobutyric acid type A receptor alpha-5 subunit-containing benzodiazepine site (alpha5-GABA_A receptor)

The Gamma-aminobutyric acid type A (GABA-A) receptor alpha-5 subunit-containing benzodiazepine site is a specialized pharmacological target located primarily in the hippocampus and cerebral cortex (UniProt P31644). This receptor is a pentameric ligand-gated chloride channel where the alpha-5 subunit, in conjunction with the gamma-2 subunit, forms a high-affinity binding site for benzodiazepines and related allosteric modulators (PubMed 21610731). Unlike other GABA-A subtypes that mediate rapid phasic inhibition, alpha-5-containing receptors are predominantly extrasynaptic and provide tonic inhibition, which is essential for regulating the threshold of neuronal firing and synaptic plasticity (PubMed 35145144). This unique physiological role makes the site a key target for treating cognitive disorders; negative allosteric modulators (NAMs) like Basmisanil are developed to enhance memory and learning by reducing excessive tonic inhibition (PubMed 25160508). Conversely, positive allosteric modulators (PAMs) are being investigated for their potential to alleviate symptoms of depression and chronic pain. The high degree of regional localization in the brain offers a therapeutic window to modulate cognition with reduced side effects compared to non-selective GABAergic drugs.

Other names

GABRA5Alpha-5 GABA-A receptorAlpha5-containing GABA-A receptorHippocampal GABA-A receptoralpha5IA site

Allosteric modulation (positive or negative) of the GABA-A receptor at the interface of the alpha-5 and gamma-2 subunits to alter chloride ion conductance.