Early onset of spontaneous activity in uninjured C-fiber nociceptors after injury to neighboring nerve fibers.

摘要: Ligation and transection of the L5 spinal nerve in rat lead to behavioral signs pain hyperalgesia. Discharge injured nociceptors has been presumed play a role generating pain. However, A fibers, but not C have shown develop spontaneous activity. Moreover, an dorsal root rhizotomy does reverse this behavior, suggesting that signals from other uninjured nerves are involved. We asked if abnormal activity develops adjacent, root. Single fiber recordings were made L4 after ligation nerve. Within 1 d lesion, developed approximately half afferents. This was at low level (median rate, seven action potentials/5 min), originated distal ganglion, present nociceptive fibers with cutaneous receptive fields. The incidence similar week injury. early onset afferents could be signal produces central sensitization responsible for development mechanical Because comingle degenerating axons peripheral nerve, we hypothesize products associated Wallerian degeneration alteration properties