Immunostaining of wild-type (Cx36 +/+) and Cx36-deficient (Cx36 −/−) mouse retina with polyclonal antibodies against glycine. A, C, Normarski images.B, D, Negative confocal micrographs of glycine immunofluorescence. In the wild-type retina (B), glycinergic amacrine cells display strong immunoreactivity. Cone bipolar cells show a weaker but still significant labeling. Staining of glycinergic amacrine cells in the Cx36 −/− retina (D) is comparable with that of the wild-type, whereas only a few bipolar cells appear glycine positive. Scale bars: 25 μm. ONL, Outer nuclear layer; INL, inner nuclear layer; IPL, inner plexiform layer.