| Cardioprotection conferred by exercise training is blunted by blockade of the opioid system. | |
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MedLine Citation:
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PMID: 21437452 Owner: NLM Status: In-Data-Review |
Abstract/OtherAbstract:
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OBJECTIVES: To investigate the effect of opioid receptor blockade on the myocardial protection conferred by chronic exercise and to compare exercise training with different strategies of myocardial protection (opioid infusion and brief periods of ischemia-reperfusion) preceding irreversible left anterior descending coronary ligation. INTRODUCTION: The acute cardioprotective effects of exercise training are at least partly mediated through opioid receptor-dependent mechanisms in ischemia-reperfusion models. METHODS: Male Wistar rats (n = 76) were randomly assigned to 7 groups: (1) control; (2) exercise training; (3) morphine; (4) intermittent ischemia-reperfusion (three alternating periods of left anterior descending coronary occlusion and reperfusion); (5) exercise training+morphine; (6) naloxone (a non-selective opioid receptor blocker) plus morphine; (7) naloxone before each exercise-training session. Myocardial infarction was established in all groups by left anterior descending coronary ligation. Exercise training was performed on a treadmill for 60 minutes, 5 times/week, for 12 weeks, at 60% peak oxygen (peak VO2). Infarct size was histologically evaluated. RESULTS: Exercise training significantly increased exercise capacity and ΔVO2 (VO2 peak - VO2 rest) (p<0.01 vs. sedentary groups). Compared with control, all treatment groups except morphine plus naloxone and exercise training plus naloxone showed a smaller infarcted area (p<0.05). No additional decrease in infarct size occurred in the exercise training plus morphine group. No difference in myocardial capillary density (p = 0.88) was observed in any group. CONCLUSIONS: Exercise training, morphine, exercise training plus morphine and ischemia-reperfusion groups had a smaller infarcted area than the control group. The effect of chronic exercise training in decreasing infarct size seems to occur, at least in part, through the opioid receptor stimulus and not by increasing myocardial perfusion. |
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Authors:
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Tatiana F G Galvão; Katt C Matos; Patrícia C Brum; Carlos E Negrão; Protásio Lemos da Luz; Antônio Carlos P Chagas |
Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Clinics (São Paulo, Brazil) Volume: 66 ISSN: 1980-5322 ISO Abbreviation: Clinics (Sao Paulo) Publication Date: 2011 |
Date Detail:
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Created Date: 2011-03-25 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101244734 Medline TA: Clinics (Sao Paulo) Country: Brazil |
Other Details:
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Languages: eng Pagination: 151-7 Citation Subset: IM |
Affiliation:
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Heart Institute, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil, tatianafgg@einstein.br. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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