Figure 9. Effect of botulinum toxin type A (botox) on withdrawal latencies on the hot-plate test and motor performance in resiniferatoxin (RTX)-induced neuropathy.

Botox was administered through intraplantar injection on RTX treatment day 56 (RTXd56). (A∼C) Graphs show the extension ability of hindlimbs before botox treatment (A, Pre-botox), in the group of after botox treatment (B, botox) and in the saline-treated group (C, saline). There was no difference in gross appearance of hindlimb extension among the 3 groups. (D) The graph shows the effect of botox on the withdrawal latency on the hot-plate test at 52°C in the saline group (open circles, n = 5) and botox group (filled circles, n = 5). On RTXd56, the withdrawal latency was normalized (arrow). Thermal hypoalgesia reappeared on post-botox day 1 (Bd1, p<0.01) and persisted until Bd5 (p<0.05). Hot-plate latencies between botox and saline groups were analyzed with two-way repeated measures ANOVA followed by Bonferroni’s post-hoc test. (E) There was no difference in retention times between the saline group (open circles, n = 5) and botox group (filled circles, n = 5) according to rotarod performance at a speed of 8 rpm (p>0.05). *p<0.05, **p<0.01, ***p<0.001.