Gamma-aminobutyric acid type A receptor subunit alpha-5 (GABRA5)

Gamma‑aminobutyric acid type A receptor subunit alpha‑5 is a protein encoded by the *GABRA5* gene. It forms part of the pentameric ligand-gated chloride channels known as GABA(A) receptors—the principal mediators of fast inhibitory neurotransmission in the mammalian brain. The most common configuration includes two α, two β, and one γ subunit; incorporation of an α‑5 subunit imparts unique pharmacological properties. Alpha‑five containing receptors are predominantly located extrasynaptically in regions such as the hippocampus where they mediate tonic inhibition but can also contribute to phasic synaptic events. These receptors play critical roles in regulating neuronal excitability, learning, memory formation, and cognitive flexibility. Altered expression or function has been implicated in several neurological conditions including developmental epilepsies and cognitive disorders. The binding sites for endogenous ligands like gamma-amino­butyric acid (GABA) are found at interfaces between specific subunits; drugs such as benzodiazepines bind at distinct sites involving the alpha-five interface with gamma-two. Selective negative modulators targeting this subtype have shown promise for enhancing cognition without sedative side effects typical of nonselective agents. Overall, Gamma-amino­butyric acid type A receptor subunit alpha‑five represents a validated therapeutic target for modulating inhibitory tone within neural circuits relevant to neuropsychiatric disease.[1][2][3][4][8]

Other names

GABA(A) receptor subunit alpha-5GABA-A receptor alpha 5GABRA5

– Positive allosteric modulation at benzodiazepine site enhances inhibitory effect by increasing chloride influx through the channel. – Negative allosteric modulators or inverse agonists reduce activity at α5-containing receptors to enhance cognition or counteract sedation/amnesia. – Selective antagonists block the action of endogenous ligands or drugs at this subunit.[2][6]