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μ‐Opioid receptor‐stimulated synthesis of reactive oxygen species is mediated via phospholipase D2
Author(s) -
Koch Thomas,
Seifert Anja,
Wu DaiFei,
Rankovic Marija,
Kraus Jürgen,
Börner Christine,
Brandenburg LarsOve,
Schröder Helmut,
Höllt Volker
Publication year - 2009
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2009.06217.x
Subject(s) - nadph oxidase , chemistry , damgo , agonist , reactive oxygen species , pld2 , microbiology and biotechnology , pharmacology , opioid receptor , biochemistry , receptor , biology , phosphatidic acid , membrane , phospholipid
We have recently shown that the activation of the rat μ‐opioid receptor (MOPr, also termed MOR1) by the μ‐agonist [ d ‐Ala 2 , Me Phe 4 , Glyol 5 ]enkephalin (DAMGO) leads to an increase in phospholipase D2 (PLD2) activity and an induction of receptor endocytosis, whereas the agonist morphine which does not induce opioid receptor endocytosis fails to activate PLD2. We report here that MOPr‐mediated activation of PLD2 stimulates production of reactive oxygen molecules via NADH/NADPH oxidase. Oxidative stress was measured with the fluorescent probe dichlorodihydrofluorescein diacetate and the role of PLD2 was assessed by the PLD inhibitor d ‐erythro‐sphingosine (sphinganine) and by PLD2‐small interfering RNA transfection. To determine whether NADH/NADPH oxidase contributes to opioid‐induced production of reactive oxygen species, μ‐agonist‐stimulated cells were pre‐treated with the flavoprotein inhibitor, diphenylene iodonium, or the specific NADPH oxidase inhibitor, apocynin. Our results demonstrate that receptor‐internalizing agonists (like DAMGO, β‐endorphin, methadone, piritramide, fentanyl, sufentanil, and etonitazene) strongly induce NADH/NADPH‐mediated ROS synthesis via PLD‐dependent signaling pathways, whereas agonists that do not induce MOPr endocytosis and PLD2 activation (like morphine, buprenorphine, hydromorphone, and oxycodone) failed to activate ROS synthesis in transfected human embryonic kidney 293 cells. These findings indicate that the agonist‐selective PLD2 activation plays a key role in the regulation of NADH/NADPH‐mediated ROS formation by opioids.