苦皮藤素IV麻醉机理的膜片钳研究

PATCH CLAMP STUDY ON THE ANESTHETICS MECHANISMS OF CELANGULIN Ⅳ

用膜片钳技术研究了植物杀虫剂苦皮藤素Ⅳ对棉铃虫幼虫离体培养中枢神经细胞钠通道门控过程的影响。结果表明,苦皮藤素Ⅳ对钠通道具有迅速的浓度依赖性阻滞作用,使电流-电压关系(I-V)曲线上移。0.1、1和10μmol/L苦皮藤素Ⅳ作用3min后,分别使钠电流峰值(INaMax)较给药前下降27.35%±4.05%、62.72%±2.81%和88.53%±5.56%(P<0.05),1和10μmol/L苦皮藤素Ⅳ还使钠通道的激活电压和峰电压分别向正电位方向移动了10mV和20mV左右。同时比较研究了利多卡因对棉铃虫幼虫神经细胞钠通道的影响,利多卡因对钠通道也具有阻滞作用,但有效作用浓度明显高于苦皮藤素Ⅳ。1、70mmol/L的利多卡因注射液作用3min后,使INaMax较用药前下降21.21%±2.52%和95.63%±2.10%(P<0.05)。苦皮藤素Ⅳ对钠通道门控过程的影响与利多卡因等局部麻醉剂非常相似,因此,对钠通道的阻滞作用可能是其发挥麻醉作用的重要机制。

The effects of botanical insecticide celangulin Ⅳon inwar d sodium current (I Na ) of the central neurons isolated from the thoracic and abdominal ganglia of cotton bollworm, Helicoverpa armigera(Hübner)were studied u sing whole-cell patch clamp technique. The recording results showed tha t celangulin Ⅳreduced I Na immediately in a concentration dependant manner and shifted up th e cur-rent-voltage relation curve. Celangulin Ⅳat 0.1, 1, 10 mol/L decreased peak I Na (I NaMax ) at 27.35%±4.05%, 62.72%±2.81%, 88.53%±5.56% respectively 3 minutes later when celangulin Ⅳwas added to the external solution. Furthermore, it revealed that celangulin Ⅳat 1, 10 mol/L shifted the active po-tential (10 mV or more) and peak curr e nt potential (20 mV or more) to the positive direction. At the same time, the effects of local anesthetics lidocaine on sodium channel of the central neurons isolated from the thoracic and abdominal ganglia of cotton bollworm were studied comparatively. The results indi-cated t hat lidocaine inhibited I Na with less potency than celangulin Ⅳ. Lidocaine at 1, 70 mmol/L de -creased I NaMax at 21.21%±2.05% and 95.63%±2.10% respectively. Taken together, the results suggested that effects of the celangulin Ⅳon the gating behav ior of sodium channels were similar to that of lido-caine. The electr ophysiological results may partially reveal the anaesthetic mechanism of celangulin Ⅳ.