Figure 8

p38 phosphorylation regulated TRPV1/A1 expression in DRG neurons. A-C: Immunostaining of p-p38 positive DRG neurons in naïve and PBS- and artemin-injected rats. The repetitive plantar injection of artemin increased the number of p-p38 positive neurons compared to in the PBS control group. D: The percentages of p-p38-labeled neurons showed that repeated artemin injection increased p-p38-labeled neurons in the DRG compared to PBS control (mean ± SEM, *p < 0.05). E and F: Colocalization of TRPV1 or TRPA1 mRNA (clusters of black grains) and p-p38 (brown cells) using the double-labeling method with ISHH and immunohistochemistry. Arrows indicate examples of double-labeled neurons. G, H: The percentages of TRPV1- (G) or TRPA1 (H)-expressing neurons from amongst p-p38-labeled neurons. Colocalization of TRPV1 or TRPA1 in p-p38-labeled neurons was significantly increased after artemin injection (mean ± SEM, *p < 0.05). Bars, 20 μm (A-C, E, F). I-K: RT-PCR of DRG primary cultured neurons with artemin (100 ng/ml) and two different doses of SB203580, 2 μM and 20 μM. The inhibition of mRNA was seen only with 20 μM of SB203580 for TRPV1 and not observed for TRPA1 (mean ± SEM, *p < 0.05; versus artemin + vehicle group).