Nerve insensitivity resistance

Herbert Oberlander coordinated the section that features chapters on sac-specific selection using chimeric genes potential applications of neuroendocrine research to insect control insect cuticle structure and metabolism molecular aspects of immune mechanisms in insects molecular genetics of nerve insensitivity resistance to insecticides and inhibition of juvenile hormone esterase by transition-state analogs. 

Some resistance factors provide only minor levels of resistance (two- to fourfold), so they would not be expected to add significantly to resistance levels. However, resistance factors normally do not occur alone. They frequently interact in a synergistic way so that the combined effect is greater than the sum of the individual effects. The most common interaction is that between penetration and metabolism. Interactions also occur between kdr and P450s, between nerve insensitivity and P450s, and between various other combinations of these factors. 

In one example (Lawrence and Casida 1984, Abalis et al. 1985) rat brain microsacs were used to test the action of cyclodiene insecticides such as dieldrin and endrin on the GABA receptors contained therein. The influx of radiolabeled CL into the microsacs via the pore channel of the receptor was inhibited by these chemicals. A similar assay was developed using microsacs from cockroach nerve. Assays with this preparation showed again the inhibitory effect of a cyclodiene (this time heptachlor epoxide) on CL influx. Also, that microsacs from cyclodiene resistant cockroaches were insensitive to the inhibitory effect of picrotoxinin, which binds to the same site on the GABA receptor (Kadous et al. 1983). 

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