坐骨神经压迫性损伤大鼠背根神经节NaN/SNS2钠通道表达的变化

THE CHANGES OF NaN/SNS2 Na~+ CHANNEL EXPRESSION IN DORSAL ROOT GANGLION NEURONS IN RATS WITH CHRONIC CONSTRICTION INJURY OF SCIATIC NERVE

摘要:

目的 :观察电压门控钠通道NaN /SNS2在大鼠坐骨神经慢性压迫性损伤 (chronicconstric tioninjury ,CCI) 14天后的变化 ,探讨慢性神经痛的发生机制。方法 :以逆转录多聚酶链反应(RT PCR)半定量分析CCI后大鼠背根神经节 (Dorsalrootgamglion ,DRG)钠通道NaN/SNS2转录物的变化 ,以及全细胞膜片钳技术记录CCI对急性分离大鼠背根神经节TTX R钠电流的影响。结果 :CCI术后 14天 ,感觉神经元特异性的TTX R钠通道转录物NaN/SNS2下调 ,与对照组相比 ,下降了大约 30 % ,TTX R钠电流密度明显减弱 ,但不影响其激活与稳态失活。其激活曲线的V1/2 分别为 - 2 6 .6 378mV、- 2 6 .6 30 6mV ,k为 6 .786 4mV、6 .732 3mV ;失活曲线的V1/2 分别为 -35 .5 84 4mV、- 37.2 188mV ,k为 8.2 792mV、8.4 6 47mV。结论 :钠通道NaN/SNS2与慢性神经痛后初级感觉神经元过度兴奋有关。

Abstract:

The present study was to investigate the changes of TTX R sodium currents and NaN/SNS2 sodium channel transcripts in DRG neurons in chronic constriction injury (CCI) of sciatic nerve 14 days after surgery. The transcript of NaN, a sensory neuron specific TTX R sodium channel, was significantly down regulated as well as the TTX R sodium current. The TTX R current density was significantly decreased in CCI group. At the same time, the properties of the TTX R currents revealed in the activation curve and steady state inactivation curve were unchanged. These results may provide at least a partial basis for the hyperexcitability of DRG neurons that contributes to hyperalgesia in this model.