Subunit-specific polyclonal antibody targeting human ρ1 GABA_C receptor

The GABA_C receptor, a postsynaptic membrane receptor expressed prominently in the retina, is a ligand-gated ion channel that consists of a combination of ρ subunits. We report characterization of a novel guinea pig polyclonal antibody, termed GABA_C Ab N-14, directed against a 14-mer peptide (N-14) of the extracellular domain of the human ρ1 subunit. The antibody exhibits high sensitivity for N-14 by ELISA. In Western blots, GABA_C Ab N-14 shows reactivity with the ρ1 subunit of preparations obtained from ρ1 GABA_C-expressing neuroblastoma cells, Xenopus oocytes, and mammalian retina and brain. Flow cytometry reveals a rightward shift in mean fluorescence intensity of GABA_C-expressing neuroblastoma cells probed with GABA_C Ab N-14. Immunostaining of neuroblastoma cells and oocytes with GABA_C Ab N-14 yields fluorescence only with GABA_C-expressing cells. Antibody binding has no effect on GABA-elicited membrane current responses. Immunostaining of human retinal sections shows preferential staining within the inner plexiform layer. GABA_C Ab N-14 appears well suited for investigative studies of GABA_C ρ1 subunit in retina and other neural tissues.