七氟醚对初级感觉神经元突触前抑制的作用

Effects of sevoflurane on presynaptic inhibition of primary sensory neurons

目的：观察七氟醚在大鼠急性分离的背根神经节（DRG）神经元上对γ-氨基丁酸（GABA）激活膜电流（IGABA）的影响，探讨七氟醚在脊髓水平的作用。方法采用全细胞膜片钳技术记录七氟醚对 IGABA的调制作用。结果（1）GABA（1～1000μmol/L）可以使86．8％（92/106）的DRG神经元产生浓度依赖性的内向电流。（2）七氟醚（30～3000μmol/L）非浓度依赖性地增强 GABA（100μmol/L）激活的电流，在300μmol/L 时增强作用最明显（P＜0．05，n＝6）。（3）七氟醚（100、300、1000μmol/L）对 GABA激活电流的增强作用与 GABA呈浓度依赖性，七氟醚对较小浓度的 GABA（10μmol/L）激活电流的增强率最大（P＜0．05，n＝6）。结论七氟醚通过增强 GABA激活的电流，增强初级感觉突触前抑制。

Objective To investigate the effects of sevoflurane on GABA-activated membrane currents（IGABA）in acutely isola-ted rat dorsal root ganglion（DRG）neurons and to discuss the effect of sevoflurane at the spinal cord level.Methods The whole-cell patch-clamp technique was adopted to record the modulating action of sevoflurane on IGABA in dorsal root ganglion neurons.Re-sults （1）GABA （1-1 000μmol/L）could make 86.8% （92/106）of the DRG neurons to produce the concentration-dependent in-ward currents.（2）Sevoflurane （30-3 000μmol/L）enhanced the GABA-activated current by non-concentration-dependence,the enhancement effect at 300μmol/L was most significant （P〈0.05,n=6）.（3）The enhancement effect of sevoflurane（100,300,1 000μmol/L）on the GABA-activated currents and GABA displayed the concentration-dependence.Sevoflurane had the maximal en-hancement rate on the smaller concentration of GABA （10μmol/L）activated current （P〈0.05,n=6）.Conclusion Sevoflurane can enhance the presynaptic inhibition of primary sensory neurons by enhancing the GABA-activated currents in DRG neurons.