Subunit-specific polyclonal antibody targeting human ρ1 GABAC receptor

The GABAC 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 GABAC 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, GABAC Ab N-14 shows reactivity with the ρ1 subunit of preparations obtained from ρ1 GABAC-expressing neuroblastoma cells, Xenopus oocytes, and mammalian retina and brain. Flow cytometry reveals a rightward shift in mean fluorescence intensity of GABAC-expressing neuroblastoma cells probed with GABAC Ab N-14. Immunostaining of neuroblastoma cells and oocytes with GABAC Ab N-14 yields fluorescence only with GABAC-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. GABAC Ab N-14 appears well suited for investigative studies of GABAC ρ1 subunit in retina and other neural tissues.