title: Mitochondrial events responsible for morphine's cardioprotection against ischemia/reperfusion injury.
abstract: Morphine may induce cardioprotection by targeting mitochondria, but little is known about the exact mitochondrial events that mediate morphine's protection. We aimed to address the role of the mitochondrial Src tyrosine kinase in morphine's protection. Isolated rat hearts were subjected to 30 min ischemia and 2h of reperfusion. Morphine was given before the onset of ischemia. Infarct size and troponin I release were measured to evaluate cardiac injury. Oxidative stress was evaluated by measuring mitochondrial protein carbonylation and mitochondrial ROS generation. HL-1 cells were subjected to simulated ischemia/reperfusion and LDH release and mitochondrial membrane potential (ΔΨm) were measured. Morphine reduced infarct size as well as cardiac troponin I release which were aborted by the selective Src tyrosine kinase inhibitors PP2 and Src-I1. Morphine also attenuated LDH release and prevented a loss of ΔΨm at reperfusion in a Src tyrosine kinase dependent manner in HL-1 cells. However, morphine failed to reduce LDH release in HL-1 cells transfected with Src siRNA. Morphine increased mitochondrial Src phosphorylation at reperfusion and this was abrogated by PP2. Morphine attenuated mitochondrial protein carbonylation and mitochondrial superoxide generation at reperfusion through Src tyrosine kinase. The inhibitory effect of morphine on the mitochondrial complex I activity was reversed by PP2. These data suggest that morphine induces cardioprotection by preventing mitochondrial oxidative stress through mitochondrial Src tyrosine kinase. Inhibition of mitochondrial complex I at reperfusion by Src tyrosine kinase may account for the prevention of mitochondrial oxidative stress by morphine.
authors.affiliation: Department of Physiology & Pathophysiology, Tianjin Medical University, Tianjin 300070, PR China; Department of Pharmacology, Tianjin Medical University, Tianjin 300070, PR China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: He
authors.affiliation: Department of Anesthesia and Pain Medicine, Medical College, Kangwon National University, Chuncheon City, Korea.
authors.forename: Jin
authors.initials: J
authors.lastname: Huh
authors.affiliation: Department of Anesthesiology, The Second Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang Province, PR China.
authors.forename: Huihua
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Pharmacology, Tianjin Medical University, Tianjin 300070, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Kang
authors.affiliation: Department of Pharmacology, Tianjin Medical University, Tianjin 300070, PR China.
authors.forename: Jianshi
authors.initials: J
authors.lastname: Lou
authors.affiliation: Department of Physiology & Pathophysiology, Tianjin Medical University, Tianjin 300070, PR China. Electronic address: zxu@tmu.edu.cn.
authors.forename: Zhelong
authors.initials: Z
authors.lastname: Xu
mesh_terms: D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D009020:Morphine / Q000494:pharmacology*; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D002316:Cardiotonic Agents; D017382:Reactive Oxygen Species; D009020:Morphine; C490511:Frk protein, rat; D019061:src-Family Kinases
keywords: Complex I activity; Mitochondrial Src tyrosine kinase; Mitochondrial oxidative stress; PP2