Gamma-aminobutyric acid type A receptor alpha4beta2delta (GABA_A receptor α4β2δ)

The Gamma-aminobutyric acid type A (GABA_A) receptor α4β2δ is a heteropentameric ligand-gated ion channel that serves as a primary mediator of tonic inhibition in the central nervous system. Unlike synaptic GABA_A receptors that facilitate rapid phasic inhibition, the α4β2δ subtype is predominantly located extrasynaptically in regions such as the thalamus, hippocampus, and cerebral cortex. These receptors are characterized by their high sensitivity to low concentrations of ambient GABA and their slow desensitization rates, which allow them to maintain a persistent inhibitory tone that regulates baseline neuronal excitability. The α4β2δ receptor is highly sensitive to modulation by neurosteroids, which act as potent positive allosteric modulators to enhance chloride conductance. Dysregulation of this receptor system is implicated in several neurological and psychiatric conditions, including catamenial epilepsy, postpartum depression, and anxiety disorders. Therapeutic agents like brexanolone and ganaxolone have been developed to target these receptors specifically, providing clinical benefits in treating mood and seizure disorders, although they are often associated with side effects such as sedation and motor incoordination.

Other names

Extrasynaptic GABA_A receptorα4β2δ GABA_A receptorDelta-containing GABA_A receptorGABAA receptor alpha4beta2delta

Positive allosteric modulation of the chloride channel to enhance tonic inhibitory currents; direct agonism at the GABA binding site.