Figure 2: Inhibition of GABAA-ρ receptors via antisense morpholino injections in the absence of damage results in a proliferative response. Tg(1016tuba1a:gfp) zebrafish were intravitreally injected with 0.75 nmol of either a control morpholino (Ctl-MO; A) or one of two independent antisense morpholinos targeting the ρ 2A subunit of the GABA ρ receptor (gabrr2a-MO1 (B, C) and gabrr2a-MO2 (D)) and then allowed to recover for 3 hours. Injected eyes were then electroporated and the fish were allowed to recover for 72 hours before sectioning. Immunostaining was performed with antibodies against PCNA or GFP to monitor DNA replication or dedifferentiation of MG, respectively. Scale bars: 50 μm in A and B. Green: tuba1a:GFP; red: PCNA; blue: TO-PRO-3 in A and B. GCL: ganglion cell layer; INL: inner nuclear layer; ONL: outer nuclear layer. Quantification of PCNA+ cells compared to control morpholinos with either gabrr2a-MO1 (C) or gabrr2a-MO2 (D). n = 7 for Ctl-MO and n = 10 for gabrr2a-MO1 (C). n = 6 for Ctl-MO and n = 7 for gabrr2a-MO2 (D). Each data point is from a separate eye and is an average of two sections, counting all PCNA+ cells in the inner nuclear layer. Two-tailed Student's t-tests were used to test for significance. Error bars indicate the mean ± SEM. ****P = 8.7 × 10–5 (C), **P = 0.0089 (D), vs. Ctl-MO. Number of optical slices: 52 (A) and 46 (B). GABA: Gamma aminobutyric acid; GFP: green fluorescent protein; PCNA: proliferating cell nuclear antigen.