Figure 3.

Kv9.1 is rapidly and robustly downregulated in DRG after nerve injury. A, Animals subjected to sham surgery retain Kv9.1 expression (i), while Kv9.1 mRNA signal is virtually absent in L5 DRG at 14 d postaxotomy (ii). All axotomized L5 DRG neurons lacking Kv9.1 signal are stained positive for the nerve injury marker ATF3 (iii). In the adjacent L4 only a minority of neurons feature loss of Kv9.1 and these are also immunoreactive for ATF3 (arrows in iv). B, C, Images and quantification of Kv9.1 transcriptional downregulation after SNT, illustrating a rapid attenuation of mRNA levels in axotomized L5 DRG as soon as 1 d postinjury, with minimal expression detected as long as day 28 (mean ± SEM; n = 4 per time point; ***p < 0.001 vs sham, one-way ANOVA with Tukey's post hoc). D, Kv9.1 protein staining is reduced 7 d postinjury in lumbar DRG neurons. E, F, Quantification of Kv9.1 protein positivity and immunoreactivity (IR), respectively, showing Kv9.1 protein downregulation in medium-large neurons (mean ± SEM; n = 3–4 per time point; **p < 0.01, ***p < 0.001 vs sham, one-way ANOVA with Tukey's post hoc). Scale bars: 50 μm.