【摘要】 选用２个对溴氰菊酯抗药性不同的粘虫种群，用１２５Ⅰ放射免疫法测定三龄幼虫头部环核苷酸水平，发现ｃＡＭＰ和ｃＧＭＰ的含量（按粘虫ｍｇ头重计）在不同发育阶段呈平坡式下降，抗性和感性种群之间的差异在于：前者ｃＡＭＰ水平较高，后者ｃＧＭＰ水平较高。溴氰菊酯处理后，感性种群ｃＡＭＰ和ｃＧＭＰ在０．５和８ｈ分别出现两次峰值；而抗性种群仅出现一次，其峰位也远低于感性种群。抗性种群的多功能氧化酶（ＭＦＯ）和酯酶的活性高于感性种群。初步认为，两种群环核苷酸变化的差异和抗性密切相关，解毒酶系活性增强是抗性机制之一。更多还原

【Abstract】 The resistant and susceptible populations of Mythimna separata Walker were selected, and cyclic nucleotide levels in their heads of third instar larvas were determined with 125 I radioimmunoassays. The results showed that the levels of cAMP and cGMP in all third instar stage presented a declining trend. After treating with deltamethrin, the levels of cAMP and cGMP in the susceptible population appeared two rising peaks at 0.5 and 8 h respectively, but the resistant population appeared the first peak only, and the value was obviously lower than that of the susceptible population. In additon, the activities of mixed function oxidase (MFO) and α NA esterase in the heads of resistant larvas raised, which could be considered as an important reason of the change about deltamethrin influence on cyclic nucleotide level.更多还原