These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Aerobic exercise reduces cardiomyocyte hypertrophy and increases contractility, Ca2+ sensitivity and SERCA-2 in rat after myocardial infarction.
    Author: Wisløff U, Loennechen JP, Currie S, Smith GL, Ellingsen Ø.
    Journal: Cardiovasc Res; 2002 Apr; 54(1):162-74. PubMed ID: 12062372.
    Abstract:
    OBJECTIVE: Although it is generally accepted that endurance training improves cardiac function after myocardial infarction the sub-cellular mechanisms are uncertain. The present study reports the effects of aerobic endurance training on myocardial mass, myocyte dimensions, contractile function, Ca2+ handling, and myofilament responsiveness to Ca2+ in cardiomyocytes from healthy and failing rat hearts. METHODS: Adult female Sprague-Dawley rats ran on a treadmill 1.5 h/day, 5 days a week for 8 weeks. Exercise intervals alternated between 8 min at 85-90% of V(O(2max)) and 2 min at 50-60%. Training started 4 weeks after ligation of the left coronary artery (TR-INF, n=11) or sham operation (TR-SHAM, n=6). Sedentary animals (SED-SHAM, n=6; SED-INF, n=13) were controls. RESULTS: After 6 weeks V(O(2max)) in TR-INF and TR-SHAM leveled off 65% above sedentary controls. In TR-SHAM, left and right ventricle weights were approximately 25% higher than in SED-SHAM, myocytes were approximately 13% longer; width remained unchanged. At physiological stimulation frequencies, relative myocyte shortening was markedly higher whereas peak systolic [Ca2+] and t(1/2) of Ca2+ transient decay were 10-20% lower, indicating higher Ca2+ sensitivity in cardiomyocytes from trained rats, compared to respective controls. In TR-INF the left and right ventricular weights, and myocyte length and width were 15, 23, 12, and 20% less than in SED-INF. Endurance training significantly increased the myocardial SR Ca2+ pump (SERCA-2) and sarcolemmal Na+-Ca2+-exchanger (NCX) protein levels to the extent that TR-INF did not differ from SED-SHAM. CONCLUSION: This is the first study to show that aerobic endurance training attenuates the ventricular and cellular hypertrophy in failing hearts. Furthermore, training consistently restores contractile function, intracellular Ca2+ handling, and Ca2+-sensitivity in cardiomyocytes from rats with myocardial infarction.
    [Abstract] [Full Text] [Related] [New Search]