有机磷与拟除虫菊酯混配在靶标部位上电生理生化分析

Analysis of Electrophysiology and Biochemistry on the Target for the Mixed Organophosphate and Pyrethroid

利用药膜法研究了氯氰菊酯不同异构体与辛硫磷以１∶１０比例混配对美洲大蠊初孵若虫的增效作用，结果显示，共毒系数均大于２００．分析了两类杀虫剂混用后对ＡＣｈＥ的离体及活体抑制，混用能增强对ＡＣｈＥ的活体抑制，在离体条件下，混用影响不大．对ＥＰＳＰ的测定结果表明，混用可缩短ＥＰＳＰ开始兴奋的时间，增大ＥＰＳＰ振幅．认为有机磷与拟除虫菊酯混用增效的原因之一是提高了对靶标酶—ＡＣｈＥ的抑制．

In bioassay against the newly hatched nymph of cockroach( Periplaneta americana )with contact method,the Co toxicity coeffcient(CTC)is shown to be higher than 200 when each of three isomers of cypermethrin is tested in 1∶10 mixture with phoxim. It can enhance the inhibition of in vivo AChE when phoxim plus cypermethrin,but it is hardly any effect on in vitro AChE.And each of these mixtures can shorten the excitatory time and increase the amplitude of excitatory postsynaptic potentials(EPSP) after treatment. It suggests that one of the synergistic mechanisms of mixed organophosphate and pyrethroid is to enhance the inhibition to target enzyme—AChE.