Binding of Nicotinoids and the Related Compounds to the Insect Nicotinic Acetylcholine Receptor

Abstract

In a radio receptor assay on the binding at the [3H]a-bungarotoxin binding site to the nicotinic acetylcholine receptor (nAChR) obtained from housefly and honeybee head membranes, nicotine, nornicotine, anabasine and dihydronicotyrine, all with highly basic nitrogen, had a strong binding affinity, whereas myosmine, nicotyrine and cotinine, with low basic nitrogen, did not. Structure-binding relationships of the above nicotinoids and pyridylmethyl-amines mostly coincided with the previously studied relationships to the insecticidal activity, the effect on nerve activity and the inhibition of acetylcholinesterase (AChE). Both enantiomers of nicotine had an affinity for nAChR, although the affinity was higher in the /-form than in the d-form. Imidacloprid interacted at the same site on the nAChR, but oxadiazolone, a potent AChE inhibitor, had no affinity. © 1992, Pesticide Science Society of Japan. All rights reserved.