Time-course of restoration of PARV + amacrine cells and their synaptic processes following selective lesion. Tissues were processed for indirect immunofluorescence and imaging after ERG recordings. Retinas were of zebrafish transgenic for sws2:mCherry (in blue cones) and nyx:mYFP (in a subset of bipolar neurons); in this line the mYFP is expressed in a variegated manner (Schroeter et al., 2006), therefore not all of the panels in this figure show the YFP reporter. (A) Control retina displaying characteristic pattern of PARV + amacrine cells within the inner nuclear layer (INL) and ganglion cell layer (GCL), and stripes of processes occupying inner plexiform layer (IPL) sublaminae s4 and s5 (thick arrows), which receive input from ON-bipolar neurons. (B–E) Regenerating retinas at 13 (B), 21 (C), 30 (D), and 80 days post-injury (DPI) (E). PARV + sublaminae are not recognizable at 13 and 21 DPI; rather, the PARV + processes appear as disorganized puncta within the IPL (thinner arrow in C). Hints of these layers emerge at 30 DPI (thick arrows in D). At 80 DPI, the PARV + processes form two distinct stripes that may correspond with sublaminae s4 and s5 (thick arrows in E). PARV + cell bodies are somewhat displaced from the boundary with the IPL (EAC in E, ectopic amacrine cell). ONL, outer nuclear layer; scale bar (in A, applies to all) = 50 μm.
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