对Cry3A毒素和氯菊酯杀虫剂经口注射处理的马铃薯甲虫的前肠、中肠和腿节样本的神经肌肉自发动作电位发射进行了记录.两种化合物均可呈现很典型的神经电生理症状:在初期阶段,它们均引起连放动作电位的发放程度大幅增加,而发放间隔期延长,且随着中毒加深而拉长.氯菊酯可在腿节样本引起典型高频爆排,表现出间隔非常短的静息期特征,但Cry3A毒素只在肠道样本中表现上述特征.而且Cry3A毒素可使处理甲虫的呕吐物大幅增加,而取食减少.这些结果显示处理虫的肠道神经肌肉系统较腿部神经肌肉系统对Cry3A毒素更敏感,Cry3A毒素最初的神经毒性或细胞毒性作用引起肠道活动的紊乱是其昆虫毒性作用的重要机制.%Spontaneous discharges of action potentials (AP) of neuromuscular preparations in the leg and fore-of mid-gut of the Colorado potato beetle, Leptinotarsa decemlineata were recorded in situ under the treatment of oral injection of Cry3A toxin and permethrin insecticide. Both of the two chemicals exhibited rather specific electrophysiological symptoms in the preparations: they evoked groups of action potentials with highly increased frequencies in the early stage, and led to long period of interspike resting, the duration of which increased as intoxication proceeded. Permethrin typically caused extremely high frequency discharges (overshooting) in the leg preparations and very short interspike resting periods, but the Cry3A toxin only exhibited these effects in the gut preparations. Also Cry3A toxin increased excretion dramatically and decreased feeding of the treated that in the leg and the primary neurotoxic or myotoxic action of Cry3A, causing a disturbance of the gut activity, is an important mechanism of its insect poisoning consequence.
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