七氟醚对大鼠背根神经节电压门控性离子通道的影响

Effects of sevoflurane on voltage-gated ion channels in dorsal root ganglion cells

目的 观察七氟醚对大鼠背根神经节(DRG)细胞电压门控性Na^+、K^+、Ca^(2+)离子通道的影响。方法 取SD大鼠胸段和上腰段的DRG,在32～34℃下,用胶原酶、胰蛋白酶孵育60～90 min后获取急性分离的DRG细胞。以-70mV为钳制电压,间隔10mV逐步递增测试电压至0mV,膜片钳全细胞记录DRG细胞的Na^+、K^+、Ca^(2+)电流。纯氧驱动七氟醚溶解于培养液,观察不同浓度七氟醚对细胞膜Na^+、K^+、Ca^(2+)电流的影响,并记录细胞外液中七氟醚浓度。结果 与用药前比较,七氟醚在0.4、0.9、1.8mmol/L时DRG细胞的Na^+、K^+电流差异无显著性(P>0.05),而七氟醚在0.4mmol/L时Ca^(2+)电流明显受抑制(P<0.05)。结论 七氟醚在脊髓水平的抗伤害感受作用可能与其抑制DRG细胞Ca^(2+)电流的作用有关。

Objective To study the effects of sevoflurane on voltage-gated Na^+, K^+ and Ca^(2+) channels in rat dorsal root ganglion(DRG) cells.Methods Dorsal root ganglions were dissected from thoracic and upper lumbar segments of the spinal cord. DRG cells were prepared by digestion with collagenase and trypsin at 32-34℃ The whole cell Na^+, K^+ and Ca^(2+) currents were recorded by standard patch clamp technique. The changes in the currents from holding potential of-70 mV to test potential of 0 mV were recorded in a 10 mV increments in the presence and absence of sevoflurane. Results 0.4, 0.9 and 1.8 mmol·L^(-1) sevoflurane had no effect on Na^+ or K^+ currents but Ca^(2+) currents could be significantly suppressed by 0.4 mmol·L^(-1) sevoflurane. Conclusion Na^+ and K^+ channels in DRG cells are not involved in the spinal mechanism of sevoflurane. The inhibition of Ca^(2+) current in DRG cells by sevoflurane could be associated with the antinociceptive effect of sevoflurane at the spinal cord level.