Potentiating and blocking actions of neonicotinoids on the response to acetylcholine of the neuronal α4β2 nicotinic acetylcholine receptor

Abstract

Effects of imidacloprid, clothianidin, thiacloprid and related compounds on the acetylcholine (ACh)-induced response of the recombinant, expressed chicken α4β2 nicotinic acetylcholine receptor (nAChR) were investigated using voltage-clamp electrophysiology. Imidacloprid and clothianidin enhanced the amplitude of the response to ACh of α4β2 nAChR. In complete contrast, thiacloprid attenuated the amplitude of the response to ACh of α4β2 nAChR. Replacing the nitro group of imidacloprid by a cyano group abolished the potentiating action, whereas exchanging the cyano group of thiacloprid for a nitro group conferred the ability to potentiate the ACh response. All three neonicotinoids shifted the ACh concentration–response curve without influencing the peak current amplitude of the ACh response.