Mediation of Sarcoplasmic Reticulum Disruption in the Ischemic Myocardium: Proposed Mechanism by the Interaction of Hydrogen Ions and Oxygen Free Radicals

  • M. L. Hess
  • Steven Krause
  • H. A. Kontos
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 161)


Acute myocardial ischemia results in a decrease in developed tension and an increase in resting tension. A breakdown of the excitation-contraction coupling system can explain the behavior of the ischemic muscle at a subcellular level. We have identified a specific defect in the sarcoplasmic reticulum (SR) from the ischemic myocardium; i.e., the uncoupling of calcium transport from ATP hydrolysis. The mediators of this excitation-contraction uncoupling process have not been identified. It is now established that the intracellular pH of the ischemic myocardium is in the range of 6.4 but the role of protons and potential role of free radicals have not been identified. We have hypothesized that protons and free radicals may interact to produce the excitation-contraction uncoupling of the ischemic myocardium. Cardiac SR was isolated from the wall of canine left ventricle and calcium uptake velocity and Ca2+ stimulated-Mg2+ dependent ATPase activity determined. Increasing proton concentration between pH 7.0 and 6.4 significantly reduced calcium uptake rates (pH 7.0 = 0.95 ± 0.02; 6.4 = 0.50 ± 0.02 µmoles Ca2+/ mg-min; p<0.01) with no effect on ATPase activity. Calculated coupling ratios (µmoles Ca2+ /µmoles Pi) decreased from 0.87 ± 0.06 at pH 7.0 to 0.51 ± 0.05 at pH 6.4. At pH 7.0, the generation of exogenous free radicals from the xanthine-xanthine oxidase system significantly depressed both calcium uptake rates (Control = 0.95 ± 0.02; X+XO = 0.15 ± 0.02) and ATPase activity (Control = 1.05 ± 0.02; X+XO + 0.30 ± 0.01 ymoles Pi/mg-min; p<0.01). The decreases in calcium uptake and in ATPase activity were completely reversible with superoxide dismutase (SOD). At pH 6.4 in the presence of xanthine and xanthine oxidase, there is a further depression of calcium uptake rates (Control = 0.50 + 0.02; X+XO = 0.11 ± 0.01; p<0.05) but there is no SOD reversible component. The addition of SOD + 20mM mannitol normalized calcium transport at pH6.4. The calculated coupling ratio at pH 6.4 in the presence of free radicals was 0.13. In contrast sarcoplasmic reticulum isolated from ischemic myocardium demonstrated a significant depression of calcium uptake rates at pH 7.1 which was further accentuated at pH 6.4. Ca2+-ATPase was significantly depressed at pH 7.1 but there was no accentuation at pH 6.4. It is concluded that no single species of free radical can explain the intarcellular excitation-contraction uncoupling of the ischemic myocardium. The system can be explained by the interaction of hydrogen ions and superoxide anions producing both injury to the sarcoplasmic reticulum and the formation of lipid free radicals with hydroxyl-like activity.


ATPase Activity Sarcoplasmic Reticulum Calcium Uptake Xanthine Oxidase Calcium Transport 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Arkhipenko, V., Bilenko, M. V., Dobrina, S. K., Kagan, V. E., Kozlou, Y. P. & Shelenkoua, L. N. Ischemic damage to sarcoplasmic reticulum of skeletal muscle: role of lipid peroxidation. Bull. Exp. Biol. Med. 83, 683–686 (1977).CrossRefGoogle Scholar
  2. 2.
    Arkhipenko, V., Gazdarou, A. K., Kagan, V. E., Kozlou, Y. P. & Spirichev, V. B. Lipid peroxidation and disturbances in Ca2+ transport through membranes of sarcoplasmic reticulum in E-vitaminosis. Bull. Exp. Biol. Med. 82, 1540–1543 (1976).Google Scholar
  3. 3.
    Boime, J., Smith, E. E. & Hunter, F. E. The role of fatty acids in mitochondrial changes during liver ischemia. Arch. Biochem. 139, 425–443 (1970).PubMedCrossRefGoogle Scholar
  4. 4.
    Cobbe, S. M. & Poole-Wilson, P. A. The time of onset and severity of acidosis in myocardial ischemia. J. Mol. Cell. Cardiol. 12, 745–760 (1980).PubMedCrossRefGoogle Scholar
  5. 5.
    Dorfman, L. M. & Adams, G. E. Reactivity of hydroxyl free radicals in aqueous solutions. NSRDS N135, No. 46, United States Department of Commerce, National Bureau of Standards (1973).Google Scholar
  6. 6.
    Fabiato, A. & Fabiato, F. Calcium and cardiac excitation-contraction coupling. Ann. Rev. Physiol. 41, 473–484 (1979).CrossRefGoogle Scholar
  7. 7.
    Feher, J., Briggs, F. N. & Hess, M. L. Characterization of cardiac sarcoplasmic reticulum from ischemic myocardium: comparison of isolated sarcoplasmic reticulum with unfractionated homogenates. J. Mol. Cell. Cardiol. 12, 427–432 (1980).PubMedCrossRefGoogle Scholar
  8. 8.
    Fridovich, I. Hypoxia and oxygen toxicity. Adv. Neurol. 26, 255–275 (1979).PubMedGoogle Scholar
  9. 9.
    Fridovich, I. Quantitative aspects of the production of superoxide anion radical by milk xanthine oxidase, J. Biol. Chemistry 245, 4053–4057 (1970).Google Scholar
  10. 10.
    Garlick, P. A., Radda, G. K. & Seeley, J. P. Studies of acidosis in the ischemic heart by phosphorus nuclear magnetic resonance. Biochem. J. 184, 547–554 (1979).PubMedGoogle Scholar
  11. 11.
    Gevers, J. A. Generation of protons by metabolic processes in heart cells. J. Mol. Cell. Cardiol. 11, 867–877 (1977).CrossRefGoogle Scholar
  12. 12.
    Guarnieri, C., Flamigni, F. & Caldarera, C. M. Role of oxygen in the cellular damage induced by re-oxygenation of hypoxic heart. J. Mol. Cell. Cardiol. 12, 797–808 (1980).PubMedCrossRefGoogle Scholar
  13. 13.
    Haber, F. & Weiss, J. The catalytic decomposition of hydrogen peroxide by ion salts. J. Proc. Royal Soc. 147, 332–351 (1934).CrossRefGoogle Scholar
  14. 14.
    Hearse, D. J. Reperfusion of the ischemic myocardium. J. Mol. Cell. Cardiol. 9, 605–616 (1977).PubMedCrossRefGoogle Scholar
  15. 15.
    Hess, M. L., Krause, S. M., Robbins, A. D. & Greenfield, L. J. Excitation-contraction coupling in hypothermic ischemic myocardium. Am. J. Physiol. 240, H336–H341 (1981a).PubMedGoogle Scholar
  16. 16.
    Hess, M. L., Warner, M. F., Robbins, A. D., Crute, S. & Greenfield, L. J. Characterization of the excitation-contraction coupling system of the hypothermic myocardium following ischemia and reperfusion. Cardiovasc. Res. 15, 390–397 (1981b).PubMedCrossRefGoogle Scholar
  17. 17.
    Hess, M. L., Krause, S. M. & Greenfield, L. J. Assessment of hypothermic cardioplegic protection of the global ischemic myocardium. J. Thorac. Cardiovasc. Surg. 80, 293–301 (1980).PubMedGoogle Scholar
  18. 18.
    Hochstein, P. & Jain, S. K. Association of lipid peroxidation and polymerization of membrane proteins with erythrocyte aging. Fed. Proc. 40, 183–188 (1981).PubMedGoogle Scholar
  19. 19.
    Jennings, R. B. & Ganote, C. E. Structural changes in myocardium during acute ischemia. Circ. Res. (Suppl III) 35, 156–172 (1974).PubMedGoogle Scholar
  20. 20.
    King, E. J. Colorimetric determinations of phosphorous. Biochem. J. 26, 292–297 (1932).PubMedGoogle Scholar
  21. 21.
    Lefer, A. M., Araki, H. & Okamatsu, S. Beneficial actions of a free radical scavenger in traumatic shock and myocardial ischemia. Circ. Shock 8, 273–282 (1981).PubMedGoogle Scholar
  22. 22.
    Lowry, O. H., Rosenbrough, N. J., Farr, A. L. & Randall, R. J. Protein measurement with the Folin phenol reagent. J. Biol. Chem. 193, 265 (1951).PubMedGoogle Scholar
  23. 23.
    McCallister, L. P., Daiello, D. C. & Tyers, G. F. O. Morpho-metric observations of the effects of normothermic ischemic arrest on dog myocardial ultrastructure. J. Mol. Cell. Cardiol. 10, 67–80 (1978).PubMedCrossRefGoogle Scholar
  24. 24.
    McCord, J. M. & Fridovich, I. The reduction of cytochrome C by milk xanthine oxidase. J. Biol. Chem. 243, 5753–5760 (1968).PubMedGoogle Scholar
  25. 25.
    Nayler, W. G., Poole-Wilson, P. A. & Williams, A. Hypoxia and calcium. J. Mol. Cell. Cardiol. 11, 683–706 (1979).PubMedCrossRefGoogle Scholar
  26. 26.
    Schwartz, A., Wood, J. M., Allen, J. C. & Bornet, E. P., et al. Biochemical and morphological correlates of cardiac ischemia. Am. J. Cardiol. 32, 46–61 (1973).PubMedCrossRefGoogle Scholar
  27. 27.
    Solaro, R. J. & Briggs, F. N. Estimating the functional capabilities of sarcoplasmic reticulum in cardiac muscle. Circ. Res. 34, 531–539 (1974).PubMedGoogle Scholar
  28. 28.
    Tappel, A. L. Lipid peroxidation damage to cell components. Fed. Proc. 32, 1870 (1973).PubMedGoogle Scholar
  29. 29.
    Zimmerman, A. R. E., Dames, W., Hulsmann, W. D., Snijder, J., Wisse, E. & Durrer, D. Morphological changes of heart muscle caused by successive perfusion with calcium free and calcium containing solutions (Calcium paradox). Cardiovasc. Res. 1, 201–209 (1967).CrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1983

Authors and Affiliations

  • M. L. Hess
    • 1
  • Steven Krause
    • 1
  • H. A. Kontos
    • 1
  1. 1.Departments of Medicine (Cardiology) and PhysiologyMedical College of VirginiaRichmondUSA

Personalised recommendations