GABAA-rho Receptor - Nomenclature

Nomenclature

A second type of ionotropic GABA receptor, insensitive to typical allosteric modulators of GABA_A receptor channels such as benzodiazepines and barbiturates, was designated GABA_С receptor. Native responses of the GABA_C receptor type occur in retinal bipolar or horizontal cells across vertebrate species.

GABA_С receptors are exclusively composed of ρ (rho) subunits that are related to GABA_A receptor subunits. Although the term "GABA_С receptor" is frequently used, GABA_С may be viewed as a variant within the GABA_A receptor family. Others have argued that the differences between GABA_С and GABA_A receptors are large enough to justify maintaining the distinction between these two subclasses of GABA receptors. However since GABA_С receptors are closely related in sequence, structure, and function to GABA_A receptors and since other GABA_A receptors besides those containing ρ subunits appear to exhibit GABA_С pharmacology, the Nomenclature Committee of the IUPHAR has recommend that the GABA_С term no longer be used and these ρ receptors should be designated as the ρ subfamily of the GABA_A receptors (GABA_A-ρ).