Mode Of Action Of Neonicotinoid Insecticides Imidacloprid And Thiacloprid To The Cockroach Pame Alpha 7 Nicotinic Acetylcholine Receptor

The functional expression of the cockroach Pame alpha 7 nicotinic acetylcholine receptor subunit has been previously studied, and was found to be able to form a homomeric receptor when expressed in Xenopus laevis oocytes. In this study, we found that the neonicotinoid insecticide imidacloprid is unable to activate the cockroach Pame alpha 7 receptor, although thiacloprid induces low inward currents, suggesting that it is a partial agonist. In addition, the co-application or 5 min pretreatment with 10 mu M imidacloprid increased nicotine current amplitudes, while the co-application or 5 min pretreatment with 10 mu M thiacloprid decreased nicotine-evoked current amplitudes by 54% and 28%, respectively. This suggesting that these two representatives of neonicotinoid insecticides bind differently to the cockroach Pame alpha 7 receptor. Interestingly, the docking models demonstrate that the orientation and interactions of the two insecticides in the cockroach Pame alpha 7 nAChR binding pocket are very similar. Electrophysiological results have provided evidence to suggest that imidacloprid and thiacloprid could act as modulators of the cockroach Pame alpha 7 receptors.