title: The role of reactive oxygen species in morphine addiction of SH-SY5Y cells.
abstract: OBJECTIVE
  The alteration of ROS level is frequently observed in the course of morphine addiction, and ROS is proverbially involved in this process. This study aims to explore the relationship among morphine addiction, reactive oxygen species (ROS) and expression of μ-opioid receptor (MOR) in differentiated SH-SY5Y cells.
  
  
  METHODS
  SH-SY5Y cells were induced to differentiation by treatment with retinoic acid (RA); the activity of lactate dehydrogenase (LDH) and the nitro blue tetrazolium (NBT) reduction were assessed by spectrophotometry. Intracellular reactive oxygen species (ROS) was measured with the 2,7-dichlorofluorescin diacetate (DCFH-DA) assay. Cellular cAMP was determined by using a competitive protein binding kit. The mRNA expression of μ-opioid receptor (MOR) was evaluated by qRT-PCR.
  
  
  RESULTS
  Morphine-induced ROS are generated in a concentration- and time-dependent manner and inhibited by naloxone. Exogenous oxidants increase the level of ROS and aggravate morphine addiction, while the exogenous antioxidants efficiently reverse these effects. Morphine decreases the mRNA level of MOR in a concentration-dependent manner. And the mRNA level of MOR is remarkably reduced in the presence of exogenous oxidants and effectively promoted by antioxidants.
  
  
  CONCLUSIONS
  This study indicates that ROS can affect morphine addiction through involving MOR. Treatment with ROS scavenging can serve as a medical therapy for morphine addiction.
authors.affiliation: Binzhou Medical University, Yantai 264000, Shandong, China; Life Science School, Yantai University, Yantai 264000, Shandong, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
authors.affiliation: Key Laboratory of Xinjiang Endemic Phytomedicine Resources, Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832002, Xinjiang, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Yuan
authors.affiliation: Binzhou Medical University, Yantai 264000, Shandong, China.
authors.forename: Hengyi
authors.initials: H
authors.lastname: Qu
authors.affiliation: Key Laboratory of Xinjiang Endemic Phytomedicine Resources, Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832002, Xinjiang, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Qianfoshan Hospital of Shandong Province, Jinan 250014, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: Binzhou Medical University, Yantai 264000, Shandong, China. Electronic address: Sunxiling@sohu.com.
authors.forename: Xiling
authors.initials: X
authors.lastname: Sun
authors.affiliation: Binzhou Medical University, Yantai 264000, Shandong, China; Life Science School, Yantai University, Yantai 264000, Shandong, China. Electronic address: zqsyt@sohu.com.
authors.forename: Qiusheng
authors.initials: Q
authors.lastname: Zheng
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009021:Morphine Dependence / Q000503:physiopathology*; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009447:Neuroblastoma / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000235:genetics*; D013997:Time Factors; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D000701:Analgesics, Opioid; D000975:Antioxidants; D009292:Narcotic Antagonists; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D017450:Receptors, Opioid, mu; D009270:Naloxone; D014212:Tretinoin; D009020:Morphine; D000242:Cyclic AMP
keywords: Morphine addiction; Reactive oxygen species (ROS); μ-Opioid receptor (MOR)