苯佐卡因对大鼠背根神经节神经元河豚毒素不敏感型钠离子通道的影响

摘要

目的 研究苯佐卡因(BZC)对大鼠背根神经节(DRG)神经元河豚毒素不敏感型(TTX-r)钠电流的影响,探讨其镇痛作用的机制.方法 酶解法分离新生大鼠单个DRG神经元,应用全细胞膜片钳技术记录不同浓度BZC对TTX-r钠电流的影响.结果 BZC浓度依赖性静息阻断TTX-r钠电流,30、100和300 μmol·L-1的BZC分别使TTX-r钠电流峰值抑制率达(18.83 ± 8.51)%、(33.08 ± 9.19)%、(58.91 ± 12.02)%,并使TTX-r钠电流稳态失活曲线浓度依赖性向超极化方向移动.结论 BZC浓度依赖性阻断DRG神经元TTX-r钠离子通道并改变通道的失活,可能是其影响痛觉传导通路以及产生镇痛作用的机制之一.%Aim To investigate the effects of benzo-caine ( BZC ) on tetrodotoxin-resistant ( TTX-r ) Na+ currents in the rat dorsal root ganglion ( DRG ) neurons. Methods Neonatal rat DRG cells were isolated and the effects of BZC on TTX-r Na + currents were observed by whole cell patch clamp recordings. Results BZC tonically blocked the TTX-r Na+ currents con-centration-dependently, and the percentages of block by 30, 100 and 300 μnol. L-1 BZC on TTX-r Na + currents were ( 18. 83 ± 8.51 )% , ( 33.08 ± 9. 19 )% and ( 58. 91 ± 12. 02 )% respectively. Inaddition, BZC shifted the steady-state inactivation curves of TTX-r Na+ currents to the hyperpolarization direction, also in a concentration-dependent manner. Conclusion BZC may induce analgesic effect by inhibiting TTX-r Na + currents of DRG neurons and shifting steady-state inactivation curves to more negative potential values.