Molecular mechanism of selective toxicity of neonicotinoids

Abstract

Actions of neonicotinoids on wild-type and mutant α7 nicotinic receptors were investigated using voltage-clamp electrophysiology to elucidate the mechanism underlying the selectivity of neonicotinoids to insect nicotinic acetylcholine receptors. It was found that when neonicotinoids bind to the receptor, the nitro group is located close to loops D and F, which was supported by the models of the agonist binding domain of the α7 nicotinic receptor. Structural features of Drosophila Dα2 subunit involved in interactions with imidacloprid were also studied using chimeras as well as mutant α subunits. The results suggested that the region loop B to the N-terminus, along with loop C, contributes to the selective interactions. © Pesticide Science Society of Japan.