Gamma-aminobutyric acid type A receptor (homomeric and beta-subunit-containing) (GABA_A receptor)

The Gamma-aminobutyric acid type A receptor (homomeric and beta-subunit-containing) is a specialized class of ligand-gated ion channels within the Cys-loop receptor family [2, 5]. This category primarily encompasses homomeric receptors composed of rho (ρ) subunits—formerly classified as GABA_C receptors—and receptors containing or consisting solely of beta (β) subunits [8, 12]. Unlike the ubiquitous heteromeric alpha-beta-gamma GABA_A receptors, these variants possess unique pharmacological properties, such as a characteristic insensitivity to benzodiazepines and bicuculline [6, 12]. Rho-homomeric receptors are essential for regulating signal transmission in retinal bipolar cells, where they mediate slow, non-desensitizing inhibitory currents [6, 12]. Beta-subunit homomers have been identified as proton-gated chloride channels that may contribute to tonic inhibition and are sensitive to modulation by general anesthetics [7, 11]. These receptors serve as therapeutic targets for visual disorders, epilepsy, and sleep disturbances, interacting with specific ligands like TPMPA and CACA, as well as general anesthetics like propofol and etomidate [1, 11].

Other names

GABA(A) receptorGABA_C receptorrho-containing GABA receptorHomomeric beta-GABA receptorGABA_A-rho receptor

Positive allosteric modulation of chloride conductance, direct agonism, and non-competitive antagonism (channel blocking).