Time-course of restoration of PARV + amacrine cells and their synaptic processes following extensive lesion. Tissues were processed for indirect immunofluorescence and imaging after ERG recordings. (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. Occasional stripes of PARV + processes were also observed within OFF sublaminae (thinner arrow). (B–E) Regenerating retinas at 13 (B), 45 (C), 60 (D), and 90 days post-injury (DPI) (E). PARV + sublaminae are not recognizable at 13 DPI, but can be observed at 45, 60, and 90 DPI (arrows), although these patterns are not consistent across the retina. Thick arrows again depict likely sublaminae s4 and s5, while the thinner arrows point to PARV + processes within OFF sublaminae (as in C), or disorganized processes with atypical lamination patterns (as in D). ONL, outer nuclear layer; scale bar (in A, applies to all) = 50 μm.
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