Injected and isolated ON cone bipolar cells do not display Cx36 immunoreactivity. A, ON cone bipolar cell of the mouse retina filled with Neurobiotin and visualized with streptavidin–FITC. The picture represents a superimposed stack of 34 confocal images of 200 nm each. B, Pattern of Cx36 immunoreactivity superimposed on the cell shown in A.C, Enlarged view of the axon terminal system of the same cell. Superimposed are 200 nm confocal sections of Neurobiotin and Cx36 staining. Cx36-immunoreactive puncta appear as cut vertically (arrows) or horizontally (arrowhead).D, Nomarski image of a cone bipolar cell isolated from the rat retina. E, The same cell shows immunoreactivity against recoverin and can therefore be identified as an ON cone bipolar cell. The numerous small, round cell bodies are photoreceptors that are also positive for recoverin. F, The same cell is not immunoreactive for Cx36. Scale bars: A–C, 10 μm;D–F, 10 μm.