μ-Opioid Receptor Forms a Functional Heterodimer With Cannabinoid CB_1 Receptor : Electrophysiological and FRET Assay Analysis

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Author(s)

    • Sudo Yuka SUDO Yuka
    • Department of Pharmacology, Nagasaki University Graduate School of Biomedical Sciences
    • MINAMI Koichiro
    • Department of Anesthesiology and Critical Care Medicine, Jichi Medical University
    • TAKADA Masafumi
    • Department of Anesthesiology, Nagasaki University Graduate School of Biomedical Sciences
    • MATSUBARA Takehiro
    • Department of Molecular and Cellular Biology, Nagasaki University Graduate School of Biomedical Sciences
    • KANAIDE Masato
    • Department of Anesthesiology, Nagasaki University Graduate School of Biomedical Sciences
    • TANIYAMA Kohtaro
    • Department of Pharmacology, Nagasaki University Graduate School of Biomedical Sciences
    • SUMIKAWA Koji
    • Department of Anesthesiology, Nagasaki University Graduate School of Biomedical Sciences
    • UEZONO Yasuhito
    • Department of Pharmacology, Nagasaki University Graduate School of Biomedical Sciences

Abstract

Interactions between μ-opioid receptor (μOR) and cannabinoid CB<sub>1</sub> receptor (CB<sub>1</sub>R) were examined by morphological and electrophysiological methods. In baby hamster kidney (BHK) cells coexpressing μOR fused to the yellow fluorescent protein Venus and CB<sub>1</sub>R fused to the cyan fluorescent protein Cerulean, both colors were detected on the cell surface; and fluorescence resonance energy transfer (FRET) analysis revealed that μOR and CB<sub>1</sub>R formed a heterodimer. Coimmunoprecipitation and Western blotting analyses also confirmed the heterodimers of μOR and CB<sub>1</sub>R. [<sc><font size = "-2">D</font></sc>-Ala<sup>2</sup>,<i>N</i>-Me-Phe<sup>4</sup>,Gly<sup>5</sup>-ol]enkephalin (DAMGO) or CP55,940 elicited K<sup>+</sup> currents in <i>Xenopus</i> oocytes expressing μOR or CB<sub>1</sub>R together with G protein activated-inwardly rectifying K<sup>+</sup> channels (GIRKs), respectively. In oocytes coexpressing both receptors, either of which was fused to the chimeric Gα protein G<sub>qi5</sub> that activates the phospholipase C pathway, both DAMGO and CP55,940 elicited Ca<sup>2+</sup>-activated Cl<sup>−</sup> currents, indicating that each agonist can induce responses through G<sub>qi5</sub> fused to either its own receptor or the other. Experiments with endogenous G<sub>i/o</sub> protein inactivation by pertussis toxin (PTX) supported the functional heterodimerization of μOR/CB<sub>1</sub>R through PTX-insensitive G<sub>qi5(m)</sub> fused to each receptor. Thus, μOR and CB<sub>1</sub>R form a heterodimer and transmit a signal through a common G protein. Our electrophysiological method could be useful for determination of signals mediated through heterodimerized G protein–coupled receptors.<br>

Journal

  • Journal of Pharmacological Sciences

    Journal of Pharmacological Sciences 108(3), 308-319, 2008-11-20

    The Japanese Pharmacological Society

References:  29

Cited by:  4

Codes

  • NII Article ID (NAID)
    10024593115
  • NII NACSIS-CAT ID (NCID)
    AA11806667
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    13478613
  • NDL Article ID
    9719559
  • NDL Source Classification
    ZS51(科学技術--薬学)
  • NDL Call No.
    Z53-D199
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
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