Gamma-aminobutyric acid type A receptor alpha-4 beta-2 delta (α4β2δ GABAA receptor)

The α4β2δ GABAA receptor is a pentameric ligand-gated ion channel primarily located in extrasynaptic regions of the central nervous system, such as the hippocampus, thalamus, and striatum (Belelli & Lambert, 2005, Nature Reviews Neuroscience). Unlike synaptic GABAA receptors that mediate rapid phasic inhibition, the α4β2δ subtype is characterized by its high affinity for GABA and slow desensitization, enabling it to provide a persistent tonic inhibitory current that regulates the baseline excitability of neurons (Stell et al., 2003, Nature). This receptor is uniquely sensitive to endogenous neurosteroids like allopregnanolone, which act as potent positive allosteric modulators to enhance inhibitory signaling (Kim et al., 2020, Nature). It serves as a critical therapeutic target for mood disorders, particularly postpartum depression, where drugs like brexanolone and zuranolone are used to restore GABAergic balance (Meltzer-Brody et al., 2018, The Lancet). Dysregulation of α4β2δ receptors is also implicated in the pathophysiology of epilepsy, premenstrual dysphoric disorder, and alcohol use disorders, making it a focus for novel anticonvulsant and sedative-hypnotic development (Maguire & Mody, 2008, Neuron). Its distinct pharmacological profile, including a lack of sensitivity to classical benzodiazepines, allows for selective modulation of brain state with a different safety profile than traditional GABAergic agents.

Other names

Extrasynaptic GABAA receptorDelta-containing GABAA receptorGABRA4-GABRB2-GABRD complexα4β2δ GABA(A) receptor

Positive allosteric modulation of the GABA-gated chloride channel, which enhances the tonic inhibitory current by increasing the frequency and duration of channel opening (Belelli & Lambert, 2005; Kim et al., 2020).