Xenopus oocyte expression of the recently cloned gamma-aminobutyric acid (GABA) rho 1 receptor subunit cDNA yields a pharmacologic profile characteristic of the GABAc responses described by Johnston [Benzodiazepine/GABA Receptors and Chloride Channels. Receptor Biochemistry and Methodology (R. W. Olsen and J. C. Venter, eds), Vol. 5. Alan R. Liss, New York, 57-71 (1986)] and the responses to retinal mRNA recently reported in the Xenopus expression system [Proc. Natl. Acad. Sci. USA 88:4318-4322 (1991)]. A rationale for defining GABA rho 1 as forming a GABAc receptor is discussed.