Sodium Channel Subtypes and Neuropathic Pain

摘要

Peripheral nerve injury can result in chronic neuropathic pain, in which normally painful peripheral stimuli produce severe pain (hyperalgesia), and normally nonpainful stimuli produce pain (allodynia). This state involves abnormal central processing that is initiated and maintained by abnormal peripheral input (Gracely et al. 1992). Peripheral nerve injuries are likely to include mechanical damage and local inflammation, both of which lead to development of pathological afferent activity, including ectopic discharges from axotomized afferents and spontaneous activity of sensitized nociceptors. Dynamic changes in Na~+ channels after nerve injury may play an important role in generating these abnormal activities, thus contributing to neuropathic pain. Many of the recently cloned subtypes of Na~+ channels are localized in dorsal root ganglion. (DRG) neurons. This chapter discusses the evidence linking certain Na~+ channel subtypes to the generation and maintenance of neuropathic pain.