title: Whitefly (Hemiptera: Aleyrodidae) binding site for imidacloprid and related insecticides: a putative nicotinic acetylcholine receptor.
abstract: Imidacloprid is used extensively to control sweetpotato whiteflies, Bemisia argentifolii Bellows & Perring [also known as B. tabaci (Gennadius) biotype B]. As a radioligand, [3H]imidacloprid binds rapidly to a single class of high-affinity sites in membrane preparations from whole adult whiteflies with an apparent dissociation constant of 2 nM and maximal binding capacity of 101 fmol/mg protein. Three related compounds (the nitromethylene analog of imidacloprid, acetamiprid, and nitenpyram) inhibit [3H]imidacloprid binding by 50% at 0.40, 2.9, and 57 nM, respectively. The pharmacological profile of the binding site (examined with imidacloprid and the analogs listed above, and nicotine, alpha-bungarotoxin, carbachol, acetylcholine [with paraoxon], and atropine) is consistent with that anticipated for a nicotinic acetylcholine receptor and correlates well with binding results for house fly, Musca domestica L., head membranes under the same conditions. Thus, [3H]imidacloprid is a suitable radioligand to investigate the putative nicotinic acetylcholine receptor of Bemisia and the possible modifications of this target site associated with selection of resistant strains.
authors.affiliation: Department of Environmental Science, Policy, and Management, University of California, Berkeley 94720-3112, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Chao
authors.forename: T J
authors.initials: TJ
authors.lastname: Dennehy
authors.forename: J E
authors.initials: JE
authors.lastname: Casida
mesh_terms: D000818:Animals; D001665:Binding Sites; D006430:Hemiptera; D007093:Imidazoles / Q000737:chemistry / Q000378:metabolism*; D007313:Insecta / Q000378:metabolism*; D007306:Insecticides / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D015394:Molecular Structure; D000073943:Neonicotinoids; D009574:Nitro Compounds; D011978:Receptors, Nicotinic / Q000378:metabolism*
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D011978:Receptors, Nicotinic; C082359:imidacloprid