Abstract:【Objective】 To investigate the analgesic effect of Botulinum Neurotoxin Type A(BoNT/A) on neuropathic pain induced by Lumbar 5 ventral root transaction(L5 VRT) and further to explain the underlying mechanism. 【Methods】 With use of the method of behavioral test

the effect of BoNT/A on the paw withdrawal threshold of L5 VRT rats was investigated

the effect of BoNT/A on Nav1.8 protein expression in Dorsal Root Ganglion (DRG) neurons of L5 VRT rats was observed by Western blot

the functional Nav1.8 current density in DRG neurons was recorded with whole-cell patch clamp technique as well. 【Results】 Subplantar injection of BoNT/A at 7 U/kg and 15 U/kg in the ipsilateral hindpaw reversed L5VRT induced mechanical allodynia

started 1 day after injection and persisted for at least 14 days. Further experiments found that administration of BoNT/A down-regulated the Nav1.8 expression and decreased the Nav1.8 current density in DRG neurons significantly. 【Conclusion】 The reduction of activity on the expression and function of Nav1.8 sodium channel may contribute to the long-lasting analgestic effect of BoNT/A.