Gamma-aminobutyric acid type A receptor alpha5beta2gamma2 subtype (GABAA receptor alpha5beta2gamma2 subtype) (α5-GABAAR)

The Gamma-aminobutyric acid type A (GABA_A) receptor α5βγ2 subtype is a ligand-gated chloride channel primarily located in the hippocampus and prefrontal cortex [1, 9]. Unlike most GABA_A receptors that mediate fast synaptic (phasic) inhibition, α5-containing receptors are predominantly extrasynaptic and provide a constant 'tonic' inhibitory current that regulates the threshold for neuronal firing and synaptic plasticity [1, 2, 10]. This subtype plays a critical role in cognitive processes, particularly learning and memory, making it a high-priority target for neurodegenerative and neuropsychiatric conditions [1, 4, 21]. In Alzheimer's disease and Down syndrome, excessive tonic inhibition mediated by these receptors is thought to contribute to cognitive deficits, leading to the development of negative allosteric modulators (NAMs) as potential 'cognitive enhancers' [1, 3, 13, 21]. Conversely, positive allosteric modulators (PAMs) are being explored for treating major depressive disorder and schizophrenia, where enhancing α5-mediated inhibition may restore circuit balance [1, 6, 16, 20]. While early non-selective GABA modulators like benzodiazepines cause sedation and amnesia, α5-selective agents aim to provide therapeutic benefits with a significantly improved safety profile [1, 5, 16].

Other names

Alpha5-containing GABAA receptorGABRA5-containing receptorα5β2γ2 GABAA receptorα5β3γ2 GABAA receptorExtrasynaptic GABAA receptor

Negative allosteric modulation (NAM), Positive allosteric modulation (PAM), and competitive antagonism at the benzodiazepine binding site or GABA binding site to modulate chloride ion conductance.