Figure 7. Distribution of Na_v1.1, Na_v1.2, and Na_v1.6 in horizontal cells and the outer plexiform layer

Double labeling using isoform-specific antibodies directed against Na_v1.1, Na_v1.2, or Na_v1.6 (green) and calbindin (red) was used to assess Na_v a-subunit localization in horizontal cells. A-C: Labeling for Na_v1.1 in the rat and mouse retina was most prominent in the distal outer plexiform layer (OPL; at retina shown). Rat and mouse horizontal cells and their processes showed only weak labeling for Na_v1.1. D-F: Rabbit horizontal cell bodies (H) and processes showed distinct Na_v1.1 labeling, in contrast to rat and mouse horizontal cells. Distinctive annuli of Na_v1.1 labeling were present in the rabbit OPL (arrowheads). G-I: Labeling for Na_v1.2 was present in horizontal cell bodies (H) and processes (arrows). Rat, mouse, and rabbit horizontal cells all showed similar labeling for Na_v1.2 (rat retina shown). J-L: Much of the Na_v1.6 labeling in the outer retina corresponded closely to horizontal cell bodies (H) and processes (arrows), although some additional diffuse labeling in the OPL was also present. Rat, mouse and rabbit horizontal cells all showed similar labeling for Na_v1.6 (rat retina shown). Labeling of blood vessels (bv) is non-specific. The following abbreviations were used: outer nuclear layer (ONL); an inner nuclear layer (INL). Scale bars equal 10 μm for all panels.