These authors contributed equally to this work.
Pharmacological characterization of cis-nitromethylene neonicotinoids in relation to imidacloprid binding sites in the brown planthopper, Nilaparvata lugens
Article first published online: 22 OCT 2009
© 2009 The Authors. Journal compilation © 2009 The Royal Entomological Society
Insect Molecular Biology
Volume 19, Issue 1, pages 1–8, February 2010
How to Cite
Xu, X., Bao, H., Shao, X., Zhang, Y., Yao, X., Liu, Z. and Li, Z. (2010), Pharmacological characterization of cis-nitromethylene neonicotinoids in relation to imidacloprid binding sites in the brown planthopper, Nilaparvata lugens. Insect Molecular Biology, 19: 1–8. doi: 10.1111/j.1365-2583.2009.00923.x
- Issue published online: 3 JAN 2010
- Article first published online: 22 OCT 2009
- cis-nitromethylene neonicotinoid;
- nicotinic acetylcholine receptors;
- Nilaparvata lugens;
- binding site
Neonicotinoid insecticides, such as imidacloprid, are selective agonists of the insect nicotinic acetylcholine receptors (nAChRs) and extensively used in areas of crop protection and animal health to control a variety of insect pest species. Here we describe that two cis-nitromethylene neonicotinoids (IPPA152002 and IPPA152004), recently synthesized in our laboratory, discriminated between the high and low affinity imidacloprid binding sites in the brown planthopper, Nilaparvata lugens, a major insect pest of rice crops in many parts of Asia. [3H]imidacloprid has two binding sites with different affinities (Kd value of 0.0035 ± 0.0006 nM for the high-affinity site and 1.47 ± 0.22 nM for the low-affinity site). Although the cis-nitromethylene neonicotinoids showed low displacement ability (Ki values of 0.15 ± 0.03 µM and 0.42 ± 0.07 µM for IPPA152002 and IPPA152004, respectively) against [3H]imidacloprid binding, low concentrations (0.01 µM) of IPPA152002 completely inhibited [3H]imidacloprid binding at its high-affinity site. In Xenopus oocytes co-injected with cRNA encoding Nlα1 and rat β2 subunits, obvious inward currents were detected in response to applications of IPPA152002 and IPPA152004, although the agonist potency is reduced to that of imidacloprid. The previously identified Y151S mutation in Nlα1 showed significant effects on the agonist potency of IPPA152002 and IPPA152004, such as a 75.8% and 70.6% reduction in Imax, and a 2.4- and 2.1-fold increase in EC50. This data clearly shows that the two newly described cis-nitromethylene neonicotinoids act on insect nAChRs and like imidacloprid, discriminated between high and low affinity binding sites in N. lugens native nAChRs. These compounds may be useful tools to further elucidate the pharmacology and nature of neonicotinoid binding sites.