Involvement Of Glia In Orofacial Abnormal Pain Following Trigeminal Nerve Transection In Rats

The rats showed allodynia and hyperalgesia to mechanical stimulation of the whisker pad area following inferior alveolar nerve (IAN) transection. In order to evaluate the involvement of the astrocite in this abnormal pain sensation, neuronal activity of the trigeminal spinal nucleus caudalis (Vc) neurons were analyzed. The Vc neurons were significantly strong responses to mechanical and heat stimuli of the face in IAN rats. The noxious mechanical and heat responses were significantly depressed after intrathecal injection (i. t.) administration of fluoroacetate (FA). On the other hand, the background activity and afterdischarge were no affected by FA application. These findings sug gest that glutamine expressed in the astrocyte involves in the face hyperalgesia following trigeminal nerve injury.