Bukatoxin对大鼠背根神经节神经元河豚毒素不敏感型钠离子通道电流的影响

The effects of Bukatoxin on tetrodotoxin-resistant(TTX-R) sodium current in rat dorsal root ganglion neurons

目的:研究东亚钳蝎毒素Bukatoxin对大鼠背根神经节(dorsal root ganglion,DRG)神经元河豚毒素不敏感型(tetrodotoxin-resistant,TTX-R)钠离子通道电流(INa)的影响。方法:在急性分离的大鼠DRG神经元上,应用全细胞膜片钳技术,观察Bukatoxin对DRG神经元TTX-RINa的影响。结果:Bukatoxin浓度依赖性地抑制TTX-RINa。在刺激电压为-10mV时,20、40、80μg/ml的Bukatoxin对TTX-RINa峰值的抑制率分别为(18.72±1.27)%、(27.40±4.97)%和(59.02±4.71)%。半数抑制浓度(IC50)为66.28μg/ml,Hill系数(h)为1.48;80μg/ml的Bukatoxin可以使TTX-RINa激活曲线向去极化方向移动约3mV,稳态失活曲线向超极化方向移动6mV。结论:Bukatoxin可以浓度依赖性的抑制DRG神经元上TTX-RINa,并改变TTX-RINa的激活和稳态失活特性,这可能是其降低外周伤害性信息传入,参与伤害性信息调制的机制之一。

Objective：To study the effects of Bukatoxin on tetrodotoxin-resistant （TTX-R） sodium currents in rat dorsal root ganglion neurons. Methods：The effects of Bukatoxin on TTX-R sodium currents was studied using the whole-cell patch clamp technique in flesh isolated rat dorsal root ganglion neurons. Results：Bukatoxin inhibited TTX-R sodium currents concentration dependently. About 18.72%,27.40% and 59.02% of peak TTX-R sodium currents were inhibited by Bukatoxin at the concentration of 20,40 and 80μg/ml respectively. The activation curve of TrX-R sodium channel was slightly shifted in depolarizing direction by Bukatoxin and the inactivation curve was shifted in hyperpolarizing direction for about 6 mV. Conclusion： Bukatoxin inhibited the TTX-R sodium currents in dose dependent manner, and changed the activation and inactivation of TTX-R sodium channel. This may count for the modulation of Bukatoxint to the nociception transduction.