Journal of Muscle Research & Cell Motility

, Volume 12, Issue 5, pp 412–424

Differential activation of myofibrils during fatigue in phasic skeletal muscle cells

  • Maria Del Carmen Garcia
  • H. Gonzalez-Serratos
  • J. P. Morgan
  • Cynthia L. Perreault
  • Monika Rozycka
Papers

DOI: 10.1007/BF01738326

Cite this article as:
Garcia, M.D.C., Gonzalez-Serratos, H., Morgan, J.P. et al. J Muscle Res Cell Motil (1991) 12: 412. doi:10.1007/BF01738326

Summary

In fatigued muscles the T-system is swollen; thus the action potential may fail to travel along the T-system or the T-tubule terminal cisternae signal may fail to bring about TC Ca2+ release. This would lead to a decrease in the number of myofibrils activated and in force development, but if fatigue is the result of a generalized process, all the myofibrils would be affected equally leading to a lower activation of all of them. We have investigated this possibility in isolated twitch muscle fibres by giving them repetitive tetanic stimulations until fatigue developed. The behaviour of myofibrils was followed with cinémicrophotography. Before fatigue, no lack of shortening of myofibrils could be found. During fatigue groups of myofibrils became wavy. When exposed to caffeine, the wavy myofibrils disappeared and tension similar to the control developed. The tension-caffeine concentration relationship was shifted to the left after development of fatigue. In low Na+ solution fatigue developed faster and after reintroducing normal Ringer, tension recovered substantially. K-contractures were smaller during fatigue. These results indicate that in this type of fatigue, a step in the EC coupling chain of events is involved in its development.

Copyright information

© Chapman and Hall Ltd 1991

Authors and Affiliations

  • Maria Del Carmen Garcia
    • 1
  • H. Gonzalez-Serratos
    • 1
  • J. P. Morgan
    • 2
  • Cynthia L. Perreault
    • 2
  • Monika Rozycka
    • 1
  1. 1.Department of BiophysicsUniversity of Maryland, School of MedicineBaltimoreUSA
  2. 2.Charles A. Dana Research Institute and the Harvard-Thorndike Laboratory of Beth Israel Hospital Department of Medicine (Cardiovascular Division)Harvard Medical SchoolUSA
  3. 3.Departamento de BiofisicaENCB, Instituto Politecnico NacionalMexico DFMexico