Gamma-aminobutyric acid type A receptor alpha-4 beta delta subtype (α4βδ GABAA receptor)

The α4βδ GABAA receptor is a specific pentameric subtype of the gamma-aminobutyric acid type A receptor, primarily localized to extrasynaptic regions of neurons in the hippocampus, thalamus, and striatum (Belelli et al., 2009, CNS & Neurological Disorders). Unlike synaptic GABAA receptors that mediate rapid phasic inhibition, the α4βδ subtype is activated by low concentrations of ambient GABA to produce a persistent tonic inhibitory current that regulates the overall excitability of the neuron (Stell et al., 2003, PNAS). This receptor is uniquely characterized by its high sensitivity to endogenous neurosteroids, such as allopregnanolone, and its relative insensitivity to classical benzodiazepines (Brown et al., 2002, British Journal of Pharmacology). Dysregulation of α4βδ receptors is implicated in the pathophysiology of several conditions, including catamenial epilepsy, postpartum depression, and premenstrual dysphoric disorder, where fluctuations in neurosteroid levels impact receptor expression and function (Maguire et al., 2005, Nature Neuroscience). Pharmacological targeting of this receptor with positive allosteric modulators like ganaxolone and brexanolone has proven effective in treating seizures and depressive symptoms by enhancing this tonic inhibitory tone (FDA Labels for Ztalmy and Zulresso). Consequently, the α4βδ GABAA receptor is a vital target for developing therapies for neuropsychiatric disorders associated with neuronal hyperexcitability.

Other names

alpha4-beta-delta GABAA receptorExtrasynaptic GABAA receptorGABRA4-GABRB-GABRD complexDelta-containing GABAA receptor

Positive allosteric modulation of extrasynaptic GABAA receptors to enhance tonic inhibitory chloride currents (Belelli et al., 2009, CNS & Neurological Disorders).