Figure 3.

P-Rex2 is absent in second-order neuronal processes in the OPL. A-C: Widefield microscopy of P-Rex2 and calbindin labeling. A: P-Rex2 labeling in photoreceptor terminals. B: Calbindin labeling in horizontal cells (H) and their processes, including the fine processes that contact ribbon synapses (arrowheads). C: Overlay of A and B. D-F: Confocal imaging of P-Rex2 and calbindin labeling. D: P-Rex2 labeling in photoreceptor terminals. E: Calbindin is present in horizontal cell processes and their fine endings in photoreceptor terminals (arrowheads). F: Overlay of panels D and E confirms that horizontal processes do not contain P-Rex2. G-I: Widefield microscopy of P-Rex2 and Synaptotagmin 2 labeling. G: P-Rex2 is present in photoreceptor terminals. H: Synaptotagmin 2 is present in horizontal (H) and bipolar cells (B) and their processes, including the fine horizontal cell processes that contact photoreceptor terminals (arrowheads). I: Overlay of panels G and H. J-L: Confocal imaging of P-Rex2 and synaptotagmin 2 labeling. J: Photoreceptor terminals show P-Rex2. K: Synaptotagmin 2 is present in bipolar and horizontal cell processes, including the fine horizontal cell processes that contact photoreceptor terminals (arrowheads). L: Overlay of J and K confirms that P-Rex2 and synaptotagmin 2 do not colocalize. M-O: Confocal imaging of P-Rex2 and PKC labeling. M: P-Rex2 is present in photoreceptor terminals. N: PKC labeling in rod bipolar cells (RB) and their dendritescontacting rod terminals (arrowheads). O: Overlay of panels M and N. Rod bipolar cell dendrites do not show P-Rex2 labeling. DAPI (blue) shows nuclear layers in A, D, G, J, and M. Confocal images shown as single optical planes of approximately 0.3 μm thickness. ONL, outer nuclear layer; OPL, outer plexiform layer; INL, inner nuclear layer. Scale bars = 20 μm for A-C and G-I; 10 μm for D-F and J-O.

Sherry and Blackburn BMC Neuroscience 2013 14:70   doi:10.1186/1471-2202-14-70
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