GABAA and GABAC receptors on mammalian rod bipolar cells

Abstract

Rod bipolar (RB) cells of mammalian retinae receive synapses from different gamma-aminobutyric acid (GABAergic) amacrine cells in the inner plexiform layer (IPL). We addressed the question whether RB cells of the rabbit and of the rat retina express different types of GABA receptors at these synapses. RB cells were immunolabeled in vertical sections of rat retinae with an antibody against protein kinase C (PKC). The sections were double-labeled for the alpha 1, alpha 2, alpha 3, or gamma 2 subunits of the GABAA receptor. Punctate immunofluorescence, which represents synaptic localization, was found for all four subunits. Many of the alpha 1-, alpha 3-, or gamma 2-immunoreactive puncta coinci..