Gamma-aminobutyric acid type A receptor alpha4beta3delta (GABAAR alpha4beta3delta)

The Gamma-aminobutyric acid type A receptor alpha4beta3delta (GABAAR alpha4beta3delta) is a pentameric ligand-gated ion channel that mediates tonic inhibition in the central nervous system [4, 9]. Unlike synaptic GABAA receptors that facilitate rapid phasic inhibition, this specific subtype is primarily located extrasynaptically and provides a persistent inhibitory tone that regulates neuronal excitability [4, 10]. It is composed of alpha 4, beta 3, and delta subunits, a combination that renders the receptor highly sensitive to neurosteroids and ethanol but insensitive to classical benzodiazepines [8, 9]. This receptor plays a pivotal role in the pathophysiology of various neuropsychiatric disorders, including postpartum depression, epilepsy, and essential tremor [1, 13, 19]. Fluctuations in endogenous neurosteroids that target this receptor are particularly linked to the onset of postpartum depression and premenstrual syndrome [7, 13]. Therapeutic agents such as brexanolone, zuranolone, and ganaxolone act as positive allosteric modulators (PAMs) at this site to enhance inhibitory signaling [13, 19]. Clinical monitoring of target engagement can be performed using biomarkers such as qEEG frontal beta power [16]. However, pharmacological activation of this receptor is associated with safety concerns including sedation, somnolence, and potential respiratory depression [14, 19].

Other names

alpha4beta3delta GABAA receptoralpha4beta3delta GABA(A) receptorGABRA4-GABRB3-GABRD receptorExtrasynaptic GABAA receptorDelta-containing GABAA receptorGABAA receptor alpha4beta3delta

Positive allosteric modulation of the GABAA receptor chloride channel, specifically at extrasynaptic sites, which enhances the inhibitory effect of GABA by increasing chloride ion influx and inducing sustained tonic inhibition of neuronal activity [4, 8, 14].