苦参碱对棉铃虫幼虫神经细胞钠通道的影响

用全细胞膜片钳技术研究了生物碱类植物杀虫剂苦参碱对棉铃虫Helicoverpa armigera幼虫离体培养中枢神经细胞钠离子通道门控过程的影响。结果表明： 苦参碱对棉铃虫幼虫神经细胞所表达的TTX （tetradotoxin, 河豚毒素)敏感钠通道具有浓度依赖性阻滞作用，1，10和100 μmol/L的苦参碱作用5 min后，分别使钠电流峰值较给药前下降（12.49±1.67）%、（18.79±2.16）%和（43.15±8.17）% (n=8, P<0.05)。苦参碱使钠电流的电流 电压关系曲线上移，但并不改变其激活电压、峰电压和电流电压关系曲线的形状。苦参碱对钠通道的阻滞作用可能是其具有某些毒理效应的离子基础。

Effects of matrine on the sodium channel in central neurons of the cotton bollworm,Helicoverpa armigera

The effects of botanical alkaloids pesticide matrine on inward sodium channel gating properties of the central neurons isolated from the thoracic and abdominal ganglia of the cotton bollworm, Helicoverpa armigera（Hübner）were studied using whole cell patch clamp technique. It was found that matrine inhibited TTX sensitive sodium current (I_na) in a concentration dependent manner. Matrine at 1, 10 and 100 μmol/L decreased peak I_na by （12.49±1.67）%, （18.79±2.16）% and （43.15±8.17）% (n=8, P<0.05), respectively in 5 minutes after matrine was added to the external solution. Matrine shifted up the current voltage relation (I-V) curve, without changing the active and peak current potential and the shape of I-V curve. The results demonstrated that matrine could inhibit Ina, which may partially explain the mechanism of its toxicity effects.