大鼠背根节神经元异位自发放电与钙依赖性钾通道的关系

Relationship between calcium dependent potassium channel and ectopic spontaneous discharge of dosal root ganglion neurons in the rat

目的：探讨神经元异位自发放电的产生机制．方法：分离背根单纤维，引导来自损伤背根节（DRG）神经元的异位自发放电，观察Ca(2+)和K+离子浓度变化及有关通道阻断剂对其的影响．结果：细胞外Ca(2+)浓度升高及应用咖啡因可抑制异位自发放电，降低其放电数；而低钙作用时则相反，使放电数增加．细胞外K+浓度升高及应用TEA等均可使异位自发放电数升高．钙依赖性钾通道特异性阻断剂Apamin可显著增加其放电数．结论：改变DRG神经元的Ca(2+)浓度显著影响异位自发放电的放电数，其作用可能是通过钙依赖性钾通道的激活或抑制所致．

Aim: To elucidate the producing mechanism ofectopic spontaneous discharge (ESD) in neurons. Methods:Single dorsal root fibre was separated, the ESD conductedfrom injured dorsal root ganglion (DRG) neurons wasrecorded and the effects of the concentration of K+ and Ca2+and channel blockers were observed. Results: During[Ca2+]. had been enchanced or caffeine used, the number ofESD were inhibited while using Ni2+ or EGTA it werefacilitated. The increment of [K+]. and TEA could bothfacilitate the ESD. Apamin, a specific antagonist of calciumdependent potossium channel K (Ca), had markedly increasingeffect on ESD. Conclusion: The change of [Ca2+] can effectthe number of ESD from injured DRG neurons, whichmaybe act through the activation or inactivation of K(Ca).