Effect of sodium ferulate on the hyperalgesia mediated by P2X3 receptor in the neuropathic pain rats.

Neuropathic pain is usually persistent and there is no effective treatment. Activation of P2X(3) receptor subtype in primary sensory neurons is involved in neuropathic pain. Sodium ferulate (SF) is an active principle from Chinese herbal medicine and has anti-inflammatory activities. This study observed the effects of SF on the hyperalgesia mediated by P2X(3) receptor of rats after chronic constriction injury (CCI). Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured and the expression of P2X(3) receptor immunoreactivity and protein in dorsal root ganglion (DRG) neurons was analyzed by immunohistochemistry and western blotting. In CCI rats treated with SF, the MWT and TWL were increased compared with CCI rats treated with normal saline. The expression of P2X(3) receptor in DRG neurons was increased after CCI. In CCI rats treated with SF, the up-regulated expression of P2X(3) receptor in DRG neurons was reduced. SF may reduce the thermal and mechanical hyperalgesia in CCI rat model by decreasing the pain transmitted by primary afferant neurons mediated by P2X(3) receptor during the chronic neuropathic pain injury.