title: Amitraz and its metabolite differentially activate α- and β-adrenergic-like octopamine receptors.
abstract: BACKGROUND
  Amitraz is a formamidine acaricide and insecticide used to control ticks, mites and fleas. N2-(2,4-Dimethylphenyl)-N1-methyformamidine (DPMF), a metabolite of amitraz, is thought to be an active agent that exerts acaricidal and insecticidal effects by acting as an agonist on octopamine receptors. The emergence of cattle ticks resistant to amitraz is a serious problem that requires urgent attention. The objective of this research was to determine which type of octopamine receptor is the primary target of amitraz and thereby understand the molecular mechanisms of action and resistance to amitraz.
  
  
  RESULTS
  Amitraz and DPMF potently activated Bombyx mori α- and β-adrenergic-like octopamine receptors (α- and β-AL OARs) that were stably expressed in HEK-293 cells. Notably, DPMF elevated intracellular cAMP levels, with an EC50of 79.6 pm in β-AL OARs, the transcripts of which were prevalently and widely localised in B. mori body parts. Furthermore, DPMF elevated the intracellular Ca2+levels, with an EC50of 1.17 nm in α-AL OARs.
  
  
  CONCLUSIONS
  Although both amitraz and DPMF acted as OAR agonists, the metabolite DPMF was more potent than amitraz and differentially activated α- and β-AL OARs. The present findings provide a basis for studies to examine the mechanism of amitraz resistance and to develop novel acaricides and insecticides. © 2016 Society of Chemical Industry.
authors.affiliation: Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan.|Present address: Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan.
authors.forename: Tomo
authors.initials: T
authors.lastname: Kita
authors.affiliation: Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ohtani
authors.affiliation: Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Takao
authors.affiliation: Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takasu
authors.affiliation: Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan.|Present address: School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, China.
authors.forename: Genyan
authors.initials: G
authors.lastname: Liu
authors.affiliation: Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Ohta
authors.affiliation: Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan.
authors.forename: Fumiyo
authors.initials: F
authors.lastname: Ozoe
authors.affiliation: Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Ozoe
mesh_terms: D056810:Acaricides / Q000378:metabolism* / Q000494:pharmacology*; D000818:Animals; D012831:Bombyx / Q000187:drug effects / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D007306:Insecticides / Q000378:metabolism* / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017982:Receptors, Biogenic Amine / Q000235:genetics / Q000378:metabolism*; D014052:Toluidines / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D056810:Acaricides; D007306:Insecticides; D012333:RNA, Messenger; D017982:Receptors, Biogenic Amine; D014052:Toluidines; C027604:norsynephrine receptor; C014983:amitraz
keywords: Bombyx mori; G protein-coupled receptor; acaricide; amitraz; insecticide; octopamine