Involvement of Phosphorylated Extracellular Signal-Regulated Kinase in Facial Neuropathic Pain Following Cervical Nerve Injury in Rats

摘要

To clarify the neural mechanisms underlying orofacial pain abnormalities after cervical nerve injury, nocifensive behavior and phosphorylated extracellular signal-regulated kinase (pERK) expression in the trigeminal spinal subnucleus caudalis (Vc) and upper cervical spinal cord (C1-C3) neurons were analyzed in the rats with cervical nerve transection (CNX). Heat hyperalgesia and mechanical allodynia were observed in CNX rats. The number of pERK-like immunoreactive cells in the Vc and C1-C3 was significantly larger in CNX rats compared to sham-operated rats following noxious stimulation of the lateral facial skin. The present findings suggested that ERK phosphorylation in Vc and C1-C3 neurons was involved in orofacial neuropathic pain following CNX.