Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Muscle Contraction: the Effect of Ionic Strength

Abstract

CONTRACTILE responses are depressed and may be abolished in muscles that are shrunken by exposure to hyperosmotic media; they are enhanced when the muscles are swollen in hyposmotic media1–4. The effects of hyperosmotic solutions have been ascribed5 to “dissociation of electromechanical coupling”, but earlier work4,6 had shown that the processes of excitation–contraction coupling were unaffected. Howarth4 therefore proposed two alternative mechanisms. He suggested that the movement of water into or out of the cell in the different osmotic conditions (i) may modify the viscosity of the myoplasm, or (ii) may affect the contractile machinery by the associated changes in the intracellular ionic strength. In our experiments, intracellular applications of calcium were used to activate contraction; thus they bypassed the factor of ec coupling. Furthermore, they were designed so as to discriminate between effects on the volume of the fibres and on the ionic strength of the intracellular phase which are both a result of changes in water content. The results demonstrate that the predominant and, perhaps, the only factor affecting the tension is the change in ionic strength. Only data on ionophoretic applications of calcium are reported here, but similar findings have also been obtained with other agents that activate contractile responses7.

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

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

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

Similar content being viewed by others

References

  1. Overton, E., Pflüg. Arch. Ges. Physiol., 92, 346 (1902).

    Article  CAS  Google Scholar 

  2. Fenn, W. O., J. Cell. Comp. Physiol., 9, 93 (1936).

    Article  Google Scholar 

  3. Hodgkin, A. L., and Horowicz, P., J. Physiol., 136, 17P (1957).

    Google Scholar 

  4. Howarth, J. V., J. Physiol., 144, 167 (1958).

    Article  CAS  Google Scholar 

  5. Sandow, A., Pharmacol. Rev., 17, 265 (1965).

    CAS  PubMed  Google Scholar 

  6. Hill, A. V., Proc. Roy. Soc., B, 148, 397 (1958).

    Article  ADS  CAS  Google Scholar 

  7. April, E., and Reuben, J. P., Fed. Proc., 27, 375 (1968).

    Google Scholar 

  8. Girardier, L., Reuben, J. P., Brandt, P. W., and Grundfest, H., J. Gen. Physiol., 47, 189 (1963).

    Article  CAS  Google Scholar 

  9. Brandt, P. W., and Grundfest, H., Fed. Proc., 27, 375 (1968).

    Google Scholar 

  10. Heilbrunn, L. V., and Wiercinski, F. J., J. Cell. Comp. Physiol., 29, 15 (1947).

    Article  CAS  Google Scholar 

  11. Caldwell, P. C., and Walser, G. E., J. Physiol., 169, 353 (1963).

    Article  CAS  Google Scholar 

  12. Reuben, J. P., Girardier, L., and Grundfest, H., J. Gen. Physiol., 47, 1141 (1964).

    Article  CAS  Google Scholar 

  13. Boyle, P. J., and Conway, E. J., J. Physiol., 100, 1 (1941).

    Article  CAS  Google Scholar 

  14. Elliott, G. F., Lowry, J., and Worthington, C. R., J. Mol. Biol., 6, 295 (1963).

    Article  Google Scholar 

  15. Brandt, P. W., Lopez, E., Reuben, J. P., and Grundfest, H., J. Cell Biol., 33, 255 (1967).

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

APRIL, E., BRANDT, P., REUBEN, J. et al. Muscle Contraction: the Effect of Ionic Strength. Nature 220, 182–184 (1968). https://doi.org/10.1038/220182a0

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1038/220182a0

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing