甲醚菊酯和溴氰菊酯在果蝇幼虫外周神经系统的协同毒理作用

本文运用细胞内微电极记录技术研究了甲醚菊酯和溴氰菊酯对果蝇Drosophila melanogaster幼虫神经一肌肉突触兴奋性接点电位(EJP₅)的影响。用甲醚菊酯(1.49x10^-8m01/L)处理后引起果蝇EJP₅的自发释放增加和刺激后的重复后自发释放。而用溴氰菊酯(1.0x10^-8mol/L)处理的则无明显影响。这显示甲醚菊酯对果蝇外周神经主要为I型毒理作用。而溴氰菊酯则主要为Ⅱ型作用，甲醚菊酯和溴氰菊酯联合应用后，则产生兼具I型和II型特征的自发释放或诱发EJP₅发放。自发释放或重复后自发释放的频率和幅值随联合处理中甲醚菊脂和溴氰菊酯的配比而变化。这些结果说明甲醚菊酯和溴氰菊酯对果蝇幼虫外周神经的毒理具有协同作用。

ELECTROPHYSIOLOGICAL JOINT ACTION OF METHOTHRIN AND DELTAMETHRIN ON THE PERIPHERAL NERVOUS SYSTEM OF DROSOPHILA LARVAE

Electrophysiological effects of methothrin and deltamethrin on theexcitatory junction potentials (EJPs ) of the Drosophila larval neuromuscular junction were recorded by using an intracellular microelectrode. M ethothrin (1.49 x10^-8mol/L) caused high frequency spontaneous EJP spikes and repetitive discharges, while deltamethrin (1.0 x 10^-8mol/L) did not. This study revealed that methothrin could produce hyperexcitation (Type I action) in the peripheral nervous system of the Drosophila larvae, but deltamethrin did not (Type II action ).Combined application of methothrin and deltamethrin resulted in a compositeaction type, which showed both Type I and Type II action on spontaneous or stimulated EJPs. The frequency and duration of repetitive discharges or spontaneous spikes in the combined treatment were changed according to the proportions of methothrin and deltamethrin. This suggests that there may be a noncompetitive interaction between methothrin and deltamethrin during their joint action on the peripheral nervous system of the Drosophila larvae.