Skip to main content
NCBI home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1972 Jun;223(2):483–505. doi: 10.1113/jphysiol.1972.sp009859

The time course of potassium contracture of single muscle fibres

Carlo Caputo
PMCID: PMC1331459  PMID: 5039284

Abstract

1. At 3° C the long duration of potassium contractures and the delay in the repriming process allow one to carry out solution changes while the responses are still in progress, making it possible to study the processes that determine the contracture time course.

2. The contractures can be cut short by suddenly lowering the external potassium concentration to normal values. Re-exposure to the high potassium medium causes the fibres to redevelop tension, in a way that depends on the time at which the original response was interrupted.

3. The period of interruption can be prolonged beyond the duration of the original contracture without affecting the second response. This redevelopment of tension is not associated with repriming since this process is much delayed. For thirty-five interrupted contractures the mean of the sum of the time integrals of tension in the two responses amounts to 98% of the mean of the time integral of tension in the uninterrupted contractures.

4. Addition of tetracaine or removal of calcium also causes the fibre to relax from a potassium contracture, although at a slower rate than that obtained by lowering the external potassium concentration. In these cases, however, no tension is redeveloped when the standard contracture medium is reapplied. When calcium in the contracture medium is replaced by nickel, the contracture time course is not diminished.

5. The results obtained with potassium contractures clearly show that the contractile activator is released continuously during a contracture. The prolonged time course of contractile responses in the cold can be explained at least in part by a prolonged release of calcium. There are no reasons to believe that at low temperature there is more activator available for release, and therefore it can be concluded that in the cold release of calcium proceeds at a slower rate.

6. Release of calcium is under control of the membrane potential, and its time course can be determined either by a fixed store of available calcium that is depleted or by a membrane mechanism which is activated upon depolarization and later inactivates with time. The evidence obtained in the present work does not allow one to decide in favour of one of these two possibilities. However, the fact that contractures are prolonged in the cold, and the finding that repriming is delayed, can be utilized in further studies to clarify the mechanism that controls the release of calcium.

Full text

PDF
483

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Adrian R. H., Chandler W. K., Hodgkin A. L. Slow changes in potassium permeability in skeletal muscle. J Physiol. 1970 Jul;208(3):645–668. doi: 10.1113/jphysiol.1970.sp009140. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Adrian R. H., Chandler W. K., Hodgkin A. L. The kinetics of mechanical activation in frog muscle. J Physiol. 1969 Sep;204(1):207–230. doi: 10.1113/jphysiol.1969.sp008909. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bianchi C. P., Bolton T. C. Action of local anesthetics on coupling systems in muscle. J Pharmacol Exp Ther. 1967 Aug;157(2):388–405. [PubMed] [Google Scholar]
  4. CURTIS B. A. Some effects of Ca-free choline-Ringer solution on frog skeletal muscle. J Physiol. 1963 Apr;166:75–86. doi: 10.1113/jphysiol.1963.sp007091. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Caputo C. The effect of low temperature on the excitation-contraction coupling phenomena of frog single muscle fibres. J Physiol. 1972 Jun;223(2):461–482. doi: 10.1113/jphysiol.1972.sp009858. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. FEINSTEIN M. B. INHIBITION OF CAFFEINE RIGOR AND RADIOCALCIUM MOVEMENTS BY LOCAL ANESTHETICS IN FROG SARTORIUS MUSCLE. J Gen Physiol. 1963 Sep;47:151–172. doi: 10.1085/jgp.47.1.151. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. FRANK G. B. Effects of changes in extracellular calcium concentration on the potassium-induced contracture of frog's skeletal muscle. J Physiol. 1960 Jun;151:518–538. doi: 10.1113/jphysiol.1960.sp006457. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Fischman D. A., Swan R. C. Nickel substitution for calcium in excitation-contraction coupling of skeletal muscle. J Gen Physiol. 1967 Jul;50(6):1709–1728. doi: 10.1085/jgp.50.6.1709. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Foulks J. G., Perry F. A. The relation between external potassium concentration and the relaxation rate of potassium-induced contractures in frog skeletal muscle. J Physiol. 1966 Oct;186(2):243–260. doi: 10.1113/jphysiol.1966.sp008032. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Frankenhaeuser B., Lännergren J. The effect of calcium on the mechanical response of single twitch muscle fibres of Xenopus laevis. Acta Physiol Scand. 1967 Mar;69(3):242–254. doi: 10.1111/j.1748-1716.1967.tb03518.x. [DOI] [PubMed] [Google Scholar]
  11. HODGKIN A. L., HOROWICZ P. Potassium contractures in single muscle fibres. J Physiol. 1960 Sep;153:386–403. doi: 10.1113/jphysiol.1960.sp006541. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. HODGKIN A. L., HOROWICZ P. The influence of potassium and chloride ions on the membrane potential of single muscle fibres. J Physiol. 1959 Oct;148:127–160. doi: 10.1113/jphysiol.1959.sp006278. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. HODGKIN A. L., HUXLEY A. F. A quantitative description of membrane current and its application to conduction and excitation in nerve. J Physiol. 1952 Aug;117(4):500–544. doi: 10.1113/jphysiol.1952.sp004764. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Heistracher P., Hunt C. C. The effect of procaine on snake twitch muscle fibres. J Physiol. 1969 May;201(3):627–638. doi: 10.1113/jphysiol.1969.sp008776. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Heistracher P., Hunt C. C. The relation of membrane changes ot contraction in twitch muscle fibres. J Physiol. 1969 May;201(3):589–611. doi: 10.1113/jphysiol.1969.sp008774. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Lüttgau H. C., Oetliker H. The action of caffeine on the activation of the contractile mechanism in straited muscle fibres. J Physiol. 1968 Jan;194(1):51–74. doi: 10.1113/jphysiol.1968.sp008394. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. NAKAJIMA S., IWASAKI S., OBATA K. Delayed rectification and anomalous rectification in frog's skeletal muscle membrane. J Gen Physiol. 1962 Sep;46:97–115. doi: 10.1085/jgp.46.1.97. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES