Gamma-aminobutyric acid type A receptor α4βδ (GABAA α4βδ receptor) (GABAA α4βδ receptor)

The **gamma-aminobutyric acid type A receptor α4βδ (GABAA α4βδ receptor)** is a subtype of the GABAA receptor family, assembled from α4, β (typically β2 or β3), and δ subunits. As part of the ligand-gated ion channel (Cys-loop) superfamily, it mediates rapid inhibitory neurotransmission by permitting chloride ion influx upon activation by the neurotransmitter GABA. In contrast to the more widely-studied synaptic GABAA receptors (α1β2γ2), the α4βδ subtype is most commonly expressed extrasynaptically, where it mediates a persistent “tonic” inhibition, responding to ambient extracellular concentrations of GABA rather than to phasic (synaptic) release[1][4]. These receptors show low sensitivity to benzodiazepines but are distinctly sensitive to neurosteroids and specific agonists like gaboxadol, making them a focus for targeted drug development in epilepsy, anxiety, sleep, and certain neuropsychiatric and metabolic disorders[2][4]. Dysfunction or altered expression of this receptor subtype has been linked to epilepsy, some forms of anxiety, and other CNS pathologies. Pharmacological targeting of these receptors holds therapeutic promise, but side effects may include sedation, cognitive disturbance, and in some cases (with high-potency agonists), respiratory depression[4].

Other names

GABA-A receptor α4βδ subtypeGABAA receptor containing α4, β, and δ subunitsExtrasynaptic GABAA receptor

Positive allosteric modulators: Enhance channel opening duration or frequency (e.g., neurosteroids, gaboxadol)\nAgonists: Directly activate the receptor (e.g., muscimol, gaboxadol)\nNegative modulators/antagonists: Inhibit channel function (e.g., certain neuroactive compounds in development)\nSome agents promote tonic inhibition by enhancing extrasynaptic receptor function