Molecular mechanism of neuropathic pain aberrant expression of voltage-gated sodium and potassium channels

点击翻译按钮获取中文摘要

Kv1.1 and Kv1.2, two most closely related members of the Shaker-like gene subfamily, encode pore-forming subuaits of voltage-gated potassium (K^+) channels. To clarify physiological roles of these proteins in primary sensory afferentiation, we have performed inimunohistochemical analysis using specific antidodies. Immunoperoxidase staining of dorsal root and trigeminal ganglia revealed that strong immunoreactivity (IR) for Kv1.1 and Kv1.2 was predominant in medium- and large-sized neurons. In double-immunofluorescence experiments, the cells strongly positive for these subunits were most frequently observed in RT97 (neurofilament)-positive large neurons; but rarely in peripherin- or IB4-positive small neurons. In the spinal dorsal horn, both the aati-Kv1.1 and anti-Kv1.2 antibodies heavily staiaed the deeper laminae III-IV. At the electron microscopic level, IRs for these proteins were preferentially localized in myelinated axons with large diameter. These results suggest that voltage-gated K^+ channels composed of Kv 1.1 and/or Kv 1.2 subunits may play important roles in conducting mechanoceptive and proprioceptiye sensation from skin and muscles. Conceivably, decreased expression of these channels after injury might cause hypereexcitability of neurons, thereby leading to hyperalgegia or allodyaia.