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. Author manuscript; available in PMC: 2011 Jun 1.
Published in final edited form as: J Comp Neurol. 2010 Jun 1;518(11):2071–2089. doi: 10.1002/cne.22322

Figure 9.

Figure 9

Surviving photoreceptors promote local rod bipolar cell survival and remodeling of rod bipolar cell dendrites. A, C, E, G: Triple labeling for PKCα, SNAP-25 (a ubiquitous synaptic SNARE protein) and VGluT1 in the wildtype C57BL/6 retina at PNM9.5. A. PKCα expression identifies rod bipolar cells, which show normal morphology and stratification in the IPL. C. In the wildtype C57BL/6 retina, the presynaptic SNARE protein SNAP-25 is found in conventional and ribbon synapses in both plexiform layers. E. VGluT1 expression in the C57BL/6 retina. G. Overlay of labeling for PKCα, SNAP-25 and VGluT1 in the wildtype C57BL/6 retina. B, D, F, H: Triple labeling for PKCα, SNAP-25, and VGluT1 in the rd10 retina at PNM9.5. B. Although many rod bipolar cells are lost by PNM9.5 and most surviving rod bipolar cells have retracted their dendrites, those rod bipolar cells located near surviving cone terminals extend abnormal, thickened dendrites (arrow) toward the surviving cone terminals (asterisk, see panel F). Many ectopic cell bodies (arrowheads) and axon terminals are also present (circle). Note the sparse plexus of rod bipolar cell terminals in the IPL. D. SNAP-25 labeling appears normal in the IPL, but is highly elevated in the OPL of the rd10 retina at PNM9.5. F. A single surviving cone terminal expressing VGluT1 is present in this region of the OPL (asterisk). Labeling for VGlut1 is present in bipolar cell terminals in the ON and OFF sublaminae of the IPL. H. Overlay of labeling for PKCα, SNAP-25 and VGluT1 in the rd10 retina reveals abnormal rod bipolar cell dendrites extending toward the surviving cone terminal (asterisk). The cellular origin of the highly SNAP-25 positive processes in the outer retina is unclear. Given the dearth of photoreceptors at this late stage of degeneration, the labeling does not arise from photoreceptor terminals. Comparison of SNAP-25 and PKCα labeling indicates that elevated SNAP-25 is not associated specifically with the abnormal rod bipolar cell dendrites. Scale bar = 20 μm, all panels.