【摘要】 【目的】戊吡虫胍是将新烟碱类和缩氨脲类杀虫剂杀虫活性部分重新组合的新型杀虫剂。但对于该类杀虫剂究竟如何影响离子通道,通道门控特性和功能是如何变化目前尚未见报道。本实验旨在明确该杀虫剂是否影响电压门控钙通道和钾通道的门控过程,探究其是否为该杀虫剂的潜在作用靶标。【方法】应用全细胞膜片钳技术检测戊吡虫胍对棉铃虫Helicoverpa armigera Hübner中枢神经细胞电压门控Ca²⁺通道和K⁺通道的影响。【结果】戊吡虫胍作用后Ⅰ-Ⅴ曲线和激活曲线均向超极化方向移动10-15 mV,具有显著性统计学差异（P<0.05）。稳态失活曲线向超极化方向移动约5 mV,不具有统计学差异（P>0.05）。电压门控Ca²⁺通道峰值电流(I_peak)有不同程度的降低。随着浓度增大I_peak降低有减小的趋势。此外,1μmol·L^-1戊吡虫胍作用后钙离子的窗口电流（I_w）面积增加幅度较10μmol·L^-1和100μmol·L^-1大,为93.20%。提示在一定的测试电压下,该药物作用后处于激活状态的Ca²⁺通道数目增多。另外,其作用后电压门控钾通道I_peak降低。随着浓度增大I_peak降低有减小的趋势。同时Ⅰ-Ⅴ曲线下移,激活曲线向去极化方向移动约8 mV,不具有统计学差异（P>0.05）。这表明戊吡虫胍作用后K⁺通道在较高电位下才能激活。【结论】戊吡虫胍能够有效抑制Ca²⁺通道和K⁺通道I_peak,并使通道的激活曲线和失活曲线发生移动,影响Ca²⁺通道和K⁺通道的门控特性。表明棉铃虫中枢神经细胞上的电压门控Ca²⁺通道和K⁺通道是戊吡虫胍的潜在作用靶标之一。更多还原

【Abstract】 [Objectives]Guadipyr is a novel insecticide that has both neonicotinoid and semicarbazone insecticidal activity.How it affects ion channels and channel gating characteristics and functions is currently unknown.We examined the effects of Guadipyr on voltage-gated calcium and potassium channels,and explored whether these channels are potential targets for this pesticide.[Methods]The effects of three concentrations(1,10,and 100μmol·L^-1)of Guadipyr on Ca²⁺and K⁺ channels were studied using the patch clamp technique.[Results]All three concentrations of Guadipyr significantly（P<0.05）shifted Ca²⁺channelⅠ-Ⅴand activation curves about 10-15 mV in the negative direction.The inactivation curves of Ca²⁺channels were also shifted 5 mV towards the hyperpolarizing direction,which is a not significant shift（P>0.05）.The Ca²⁺peak current was significantly decreased by Guadipyr treatment relative to the control.The I_peak decreased more slowly as the concentration of Guadipyr increased.The area of window current increased the most（93.20%）following treatment with 1μmol·L^-1Guadipyr than by treatment with 10μmol·L^-1 and 100μmol·L^-1.The number of Ca²⁺channels activated increased after Guadipyr treatment at a test voltage of -60 mV to+10 mV.The K⁺peak current decreased gradually when Guadipyr was added to the external solution;the I_peak decreased more slowly as the Guadipyr concentration increased from 10μmol·L^-1 to 100μmol·L^-1.Ⅰ-Ⅴcurves declined and the activation of K⁺channels was shifted 8 mV towards the depolarizing direction,which was not significant（P>0.05）.This shows that K⁺channels can be activated at higher potentials by Guadipyr.[Conclusion]Guadipyr can effectively inhibit the I_peak of the Ca²⁺and K⁺channels,and shift the activation and inactivation curves of these channels,thereby affecting the gating of Ca²⁺channels and K⁺channels.Therefore,Ca²⁺and K⁺ channels in the central neurons of H.armigera are potential Guadipyr target sites.更多还原