几种杀虫剂对棉铃虫头部酯酶的联合抑制作用

测定了几种药剂及其组合对棉铃虫Helicoverpa armigera头部酯酶活性的独立与联合抑制作用。结果显示：久效磷、敌百虫、呋喃丹对酯酶活性抑制中浓度分别为:2.4443×10^-6、3.4562×10^-7、2.6302×10^-5mol/L。药代动力学分析结果显示:久效磷与呋喃丹对酯酶抑制方式为竞争性抑制,敌百虫为非竞争性抑制。久效磷+敌百虫与敌百虫+呋喃丹两种药剂组合处理后,对酯酶抑制均增强,抑制中浓度分别为:1.0846×10^-6、5.1786×10^-6mol/L,对酯酶的抑制作用属非竞争性抑制作用。而久效磷+呋喃丹组合对酯酶抑制活性相加，为竞争性抑制作用。结果说明杀虫剂与酯酶的药代动力学互作对混剂的酯酶的抑制作用方式和活性具有重要影响。

Toxicokinetic analysis of joint action of several insecticide-combinations on head esterases

Inhibition and toxicokinetic action of several insecticide-combinations on the esterases from the heads of cotton bollworm (Helicoverpa armigera Hübner) were assayed. Residue activity of the esterases assayed in vitro showed that the I₅₀ values affording 50% inhibition of monocrotophos, trichlorfon and carbofuran were 2.4443×10^-6, 3.4562×10^-7 and 2.6302×10^-5（mol/L） respectively. Graphic analysis on the toxicokinetic mode of action on the enzyme of each insecticide indicated that monocrotophos and carbofuran inhibited the enzyme competitively, while trichlorfon did the same non-competitively. Joint treatment of two insecticides with non-competitive inhibition and competitive inhibition resulted in a potentiated inhibition on the enzyme, and I₅₀ values of monocrotophos trichlorfon and trichlorfon-carbofuran were 1.0846×10^-6 and 5.1786×10^{-6 (mol/L)} respectively. On the other hand, joint treatment of two insecticides with competitive inhibition led to a competitive inhibition, but no potentiated joint action. These results suggested that the toxicokinetic interactions between the insecticides and the easterases play an important role in the joint action of the insecticide-combinations on the enzyme.