Figure 9. Schematic summarizing the subcellular distribution of calbindin-28 kDa and calretinin in the different compartments of the retinal ganglion cell. Labeling for calbindin-28 kDa or calretinin was absent from the dendritic compartment of the retinal ganglion cells (white). Many, but not all, retinal ganglion cell soma show labeling for either calbindin-28 kDa or calretinin (red). The initial segments of the retinal ganglion cells where the voltage-gated sodium channels (Na_Vs in blue) are clustered are not labeled by either calbindin-28 kDa or calretinin. Calretinin immunolabeling is concentrated at distinct locations on the retinal ganglion cell axon (dashed red line) where they are most likely membrane bound. Calbindin-28 kDa and calretinin are either diffusely coexpressed or differentially expressed in the axons (diffuse red dots), but are both absent from the initial segments.