title: Two splicing variants of a novel family of octopamine receptors with different signaling properties.
abstract: The octopamine and tyramine, as the invertebrate counterparts of the vertebrate adrenergic transmitters, control and modulate many physiological and behavioral processes. Both molecules mediate their effects by binding to specific receptors belonging to the superfamily of G-protein-coupled receptors. So far, four families of octopamine and tyramine receptors have been reported. Here, we described the functional characterization of one putative octopamine/tyramine receptor gene from the rice stem borer, Chilo suppressalis. By a mechanism of alternative splicing, this receptor gene (CsOA3) encodes two molecularly distinct transcripts, CsOA3S and CsOA3L. CsOA3L differs from CsOA3S on account of the presence of an additional 30 amino acids within the third intracellular loop. When heterologously expressed, both receptors cause increases of intracellular Ca(2+) concentration. The short form, CsOA3S, was activated by both octopamine and tyramine, resulting in decreased intracellular cAMP levels ([cAMP]i ) in a dose-dependent manner, whereas dopamine and serotonin are not effective. However, CsOA3L did not show any impact on [cAMP]i . Studies with series of agonists and antagonists confirmed that CsOA3 has a different pharmacological profile from that of other octopamine receptor families. The CsOA3 is, to our knowledge, a novel family of insect octopamine receptors.
authors.affiliation: State Key Laboratory of Rice Biology & Key Laboratory of Agricultural Entomology of Ministry of Agriculture, Institute of Insect Sciences, Zhejiang University, Hangzhou, China; Key Laboratory of Integrated Management of Crop Disease and Pests, Ministry of Education, Department of Pesticide Sciences, College of Plant Protection, Nanjing Agricultural University, Jiangsu Key Laboratory of Pesticide Sciences, Nanjing, China.
authors.forename: Shun-Fan
authors.initials: SF
authors.lastname: Wu
authors.forename: Gang
authors.initials: G
authors.lastname: Xu
authors.forename: Yi-Xiang
authors.initials: YX
authors.lastname: Qi
authors.forename: Ren-Ying
authors.initials: RY
authors.lastname: Xia
authors.forename: Jia
authors.initials: J
authors.lastname: Huang
authors.forename: Gong-Yin
authors.initials: GY
authors.lastname: Ye
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004305:Dose-Response Relationship, Drug; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009036:Moths; D009655:Octopamine / Q000494:pharmacology; D010802:Phylogeny; D020033:Protein Isoforms / Q000235:genetics* / Q000378:metabolism*; D017982:Receptors, Biogenic Amine / Q000819:agonists / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
chemical_list: D020033:Protein Isoforms; D017982:Receptors, Biogenic Amine; C027604:norsynephrine receptor; D009655:Octopamine
keywords: Ca2+ signaling; GPCR; octopamine; pharmacology; tyramine; α2-adrenergic receptors