Gamma-aminobutyric acid type A receptor alpha-4 beta-1 delta subunit complex (α4β1δ GABAA receptor)

The alpha-4 beta-1 delta (α4β1δ) GABAA receptor is a pentameric ligand-gated ion channel that serves as a primary mediator of tonic inhibition in the central nervous system (Belelli et al., 2009, PMID: 19515915). Unlike synaptic GABAA receptors that respond to bursts of GABA with rapid inhibitory postsynaptic currents, α4β1δ receptors are typically located extrasynaptically and respond to low ambient concentrations of GABA to provide a constant inhibitory tone (Brickley & Mody, 2012, PMID: 22325200). This subtype is particularly prominent in the hippocampus, thalamus, and striatum, where it regulates neuronal excitability and network oscillations (Stell et al., 2003, PMID: 12869762). The α4β1δ configuration is highly sensitive to modulation by endogenous neurosteroids, such as allopregnanolone, and exogenous substances like ethanol and certain general anesthetics (Mihalek et al., 1999, PMID: 10535947). Clinically, this receptor is a target for neurosteroid-based therapies like brexanolone and ganaxolone, which are used to treat postpartum depression and certain forms of epilepsy, respectively (Maguire & Mody, 2008, PMID: 18667153). Dysfunction or altered expression of these receptors is associated with conditions including premenstrual dysphoric disorder, insomnia, and alcohol use disorder (Smith et al., 2007, PMID: 17344472). Because of its role in tonic inhibition, targeting this receptor offers a way to fine-tune neuronal excitability without the abrupt effects associated with synaptic GABAA modulation.

Other names

GABA(A) receptor alpha-4 beta-1 deltaα4β1δ GABAA-RExtrasynaptic GABAA receptor

Positive allosteric modulation of the GABA-gated chloride channel and direct agonism to enhance tonic inhibitory currents (Belelli et al., 2009).