Gamma-aminobutyric acid receptor type A-rho (GABACR)

The Gamma-aminobutyric acid receptor type A-rho (GABA-A-rho), historically referred to as the GABA_C receptor, is a member of the Cys-loop superfamily of ligand-gated ion channels (IUPHAR/BPS Guide to Pharmacology). It is primarily composed of rho (ρ1, ρ2, and ρ3) subunits that form functional homomeric or heteromeric pentamers, which are distinct from classical GABA_A receptors due to their lack of sensitivity to bicuculline and benzodiazepines (Enz, 2001). These receptors function as chloride-selective channels that mediate slow, sustained inhibitory neurotransmission in the central nervous system, with particularly high expression in the retinal bipolar and horizontal cells (Johnston, 2002). In the retina, they play a vital role in signal processing, including the regulation of visual sensitivity and temporal resolution (Lukasiewicz, 1996). Beyond vision, GABA-A-rho receptors are involved in sleep-wake regulation and memory modulation within the hippocampus and superior colliculus (Nieto et al., 2011). Dysregulation or mutations in the GABRR genes are associated with visual disorders such as retinitis pigmentosa and myopia, as well as neuropsychiatric conditions like anxiety (Albrecht & Darlison, 1995). Pharmacological agents such as the selective antagonist TPMPA and the agonist CACA are used to study these receptors and are being investigated for their potential therapeutic applications in treating retinal diseases and neuropsychiatric conditions (Chebib & Johnston, 1999).

Other names

GABA_C receptorRho-containing GABA receptorGABRRIonotropic GABA receptor type A-rho

Ligand-gated chloride channel that mediates inhibitory neurotransmission through hyperpolarization of the postsynaptic membrane upon GABA binding (IUPHAR).