Fig. 10

The inhibitory effects of 2R, 6R-HNK on CGRP expression and allodynia are occluded by TRPA1 inhibitor menthol. a, b Representative images and RelOD statistics show the changes of TRPA1, VGLUT2 and CGRP expression in DRG neurons 24 h after the TRPA1 agonist formaldehyde (Formal, 30 μM) incubation with or without 30 μM 2R, 6R-HNK and/or 300 μM menthol. Before that, DRG neurons were planted under equal density, and test started when cells reconstructed their synaptic growth at 48 h (n = 11 samples/group). c Quantification of Trpa1, Vglut2, Bdnf and Calcα mRNA in DRG neurons in vitro from different groups 24 h after formaldehyde stimulation (n = 9 samples /group), ^*p < 0.05, ^**p < 0.01,^***p < 0.001, ^****p < 0.0001 between groups. d, e The preventive (d) and therapeutic (e) effects of TRPA1 inhibition by menthol and 2R, 6R-HNK on LF-PENS-induced mechanical pain were mostly coupled (n = 5 mice/group), ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001 compared with saline 1 d + LF-PENS or LF-PENS + saline group; ^#p < 0.05 compared with Menthol 1 d + LF-PENS or LF-PENS + menthol group