A RetroSearch Logo

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Search Query:

Showing content from https://doi.org/10.1038/345618a0 below:

Kinetics, stoichiometry and role of the Na–Ca exchange mechanism in isolated cardiac myocytes

Kinetics, stoichiometry and role of the Na–Ca exchange mechanism in isolated cardiac myocytes

Nature volume 345, pages 618–621 (1990)Cite this article

Abstract

COMPELLING evidence has existed for more than a decade for a sodium/calcium (Na–Ca) exchange mechanism in the surface membrane of mammalian heart muscle cells1–3 which exchanges about three sodium ions for each calcium ion4–6. Although it is known that cardiac muscle contraction is regulated by a transient increase in intracellular calcium ([Ca2+]i) triggered by the action potential7, the contribution of the Na–Ca exchanger to the [Ca2+]i transient and to calcium extrusion during rest is unclear. To clarify these questions, changes in [Ca2+]i were measured with indo-1 in single cardiac myocytes which were voltage clamped and dialysed with a physiological level of sodium. We find that Ca entry through the Na–Ca exchanger is too slow to affect markedly the rate of rise of the normal [Ca2+]i transient. On repolarization, Ca extrusion by the exchanger causes [Ca2+]i to decline with a time constant of 0.5 s at –80 mV. The rate of decline can be slowed e-fold with a 77-mV depolarization. Calcium extrusion by the exchanger can account for about 15% of the rate of decline of the [Ca2+]i transient (the remainder being calcium resequestration by the sarcoplasmic reticulum (SR)). The ability of the cell toextrude calcium was greatly reduced on inhibiting the exchanger by removing external sodium, which itself led to an increase in resting [Ca2+]i. This finding is in contrast to the suggestion that calcium extrusion at rest is mediated mainly by a sarcolemmal Ca-ATPase8. Near equilibrium, the properties of the Na–Ca exchanger were consistent with a stoichiometry of 3Na:1 Ca, and since the exchanger can operate in the absence of potassium, the cardiac Na–Ca exchanger must be different from that of rod outer segments9.

This is a preview of subscription content, access via your institution

Access options

Subscribe to this journal

Receive 51 print issues and online access

199,00 € per year

only 3,90 € per issue

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Additional access options: Similar content being viewed by others References

  1. Reuter, H. & Seitz, N. J. Physiol., Lond. 195, 451–470 (1968).

    Article  CAS  Google Scholar 

  2. Glitsch, H. G., Reuter, H. & Scholz, H. J. Physiol., Lond. 209, 25–43 (1970).

    Article  CAS  Google Scholar 

  3. Blaustein, M. P. J. cardiovasc. Pharmac. 12, S56–S58 (1988).

    Article  CAS  Google Scholar 

  4. Pitts, B. J. R. J. biol. Chem. 254, 6232–6235 (1979).

    CAS  PubMed  Google Scholar 

  5. Reeves, J. P. & Hale, C. C. J. biol. Chem. 259, 7733–7739 (1984).

    CAS  PubMed  Google Scholar 

  6. Ehara, T., Matsuoka, S. & Noma, A. J. Physiol., Lond. 410, 227–249 (1989).

    Article  CAS  Google Scholar 

  7. Chapman, R. A. Am. J. Physiol. 245, H535–H552 (1983).

  8. Carnoni, P. & Carafoli, E. J. biol. Chem. 256, 3263–3270 (1981).

    Google Scholar 

  9. Cervetto, L., Lagnado, L., Perry, R. J. Robinson, D. W. & McNaughton, D. A. Nature 337, 740–743 (1989).

    Article  ADS  CAS  Google Scholar 

  10. Grynkiewicz, G., Poenie, M. & Tsien, R. Y. J. biol. Chem. 260, 3440–3450 (1985).

    CAS  Google Scholar 

  11. Cannell, M. B., Berlin, J. R. & Lederer, W. J. Science 238, 1419–1423 (1987).

    Article  ADS  CAS  Google Scholar 

  12. Ellis, D. J. Physiol., Lond. 273, 211–240 (1977).

    Article  CAS  Google Scholar 

  13. Sheu, S. S. & Fozzard, H. A. J. gen. Physiol. 80, 325–351 (1982).

    Article  CAS  Google Scholar 

  14. Barcenas-Ruiz, L., Beuckelmann, D. J. & Wier, W. G. Science 238, 1720–1722 (1987).

    Article  ADS  CAS  Google Scholar 

  15. Bers, D. M. & Ellis, D. Pflugers Arch. ges. Physiol. 393, 171–178 (1982).

    Article  CAS  Google Scholar 

  16. Bridge, J. H. B., Spitzer, K. W. & Ershler, P. R. Science 241, 823–825 (1988).

    Article  ADS  CAS  Google Scholar 

  17. Baker, P. F., Blaustein, M. P. Hodgkin, A. L. & Steinhardt, R. A. J. Physiol., Lond. 200, 431–458 (1969).

    Article  CAS  Google Scholar 

  18. Gadsby, D. C., Nakao, M., Noda, M. & Shepherd, R. N. J. Physiol., Lond. 407, 135P (1988).

    Article  Google Scholar 

  19. Lagnado, L., Cervetto, L., McNaughton, P. A. Proc. natn. Acad. Sci. U.S.A. 85, 4548–4552 (1988).

    Article  ADS  CAS  Google Scholar 

  20. Hume, J. R. & Uehara, A. J. gen. Physiol. 87, 857–884 (1986).

    Article  CAS  Google Scholar 

  21. Kimura, J., Miyamae, S. & Noma, A. J. Physiol., Lond. 384, 199–222 (1987).

    Article  CAS  Google Scholar 

  22. Berlin, J. R., Cannell, M. B. & Lederer, W. J. Am. J. Physiol. 253, H1540–H1547 (1987).

    CAS  PubMed  Google Scholar 

  23. Cannell, M. B. & Lederer, W. J. Pflugers Arch. ges. Physiol. 406, 536–539 (1986).

    Article  CAS  Google Scholar 

  24. Williams, D. A., Fogarty, K. E., Tsien, R. Y. & Fay, F. S. Nature 318, 558–561 (1985).

    Article  ADS  CAS  Google Scholar 

Download references

Author information Author notes

  1. Mark B. Cannell: To whom correspondence should be addressed.

Authors and Affiliations

  1. Department of Pharmacology (R-189), University of Miami School of Medicine, PO Box 016189, Miami, Florida, 33101, USA

    Lynn M. Crespo, Christopher J. Grantham & Mark B. Cannell

Authors
  1. Lynn M. Crespo
  2. Christopher J. Grantham
  3. Mark B. Cannell
About this article Cite this article

Crespo, L., Grantham, C. & Cannell, M. Kinetics, stoichiometry and role of the Na–Ca exchange mechanism in isolated cardiac myocytes. Nature 345, 618–621 (1990). https://doi.org/10.1038/345618a0

Download citation

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4