Modulation of passive force in single skeletal muscle fibres
- 28 June 2005
- journal article
- Published by The Royal Society in Biology Letters
- Vol. 1 (3), 342-345
- https://doi.org/10.1098/rsbl.2005.0337
Abstract
In this study, we investigated the effects of activation and stretch on the passive force–sarcomere length relationship in skeletal muscle. Single fibres from the lumbrical muscle of frogs were placed at varying sarcomere lengths on the descending limb of the force–sarcomere length relationship, and tetanic contractions, active stretches and passive stretches (amplitudes ofca10% of fibre length at a speed of 40% fibre length/s) were performed. The passive forces following stretch of an activated fibre were higher than the forces measured after isometric contractions or after stretches of a passive fibre at the corresponding sarcomere length. This effect was more pronounced at increased sarcomere lengths, and the passive force–sarcomere length relationship following active stretch was shifted upwards on the force axis compared with the corresponding relationship obtained following isometric contractions or passive stretches. These results provide strong evidence for an increase in passive force that is mediated by a length-dependent combination of stretch and activation, while activation or stretch alone does not produce this effect. Based on these results and recently published findings of the effects of Ca2+on titin stiffness, we propose that the observed increase in passive force is caused by the molecular spring titin.Keywords
This publication has 21 references indexed in Scilit:
- Active force inhibition and stretch-induced force enhancement in frog muscle treated with BDMJournal of Applied Physiology, 2004
- Effects of shortening on stretch-induced force enhancement in single skeletal muscle fibersJournal of Biomechanics, 2004
- Calcium-dependent molecular spring elements in the giant protein titinProceedings of the National Academy of Sciences, 2003
- Force enhancement following muscle stretch of electrically stimulated and voluntarily activated human adductor pollicisThe Journal of Physiology, 2002
- A Non-Cross-Bridge Stiffness in Activated Frog Muscle FibersBiophysical Journal, 2002
- History-Dependent Mechanical Properties of Permeabilized Rat Soleus Muscle FibersBiophysical Journal, 2002
- Titin Extensibility In Situ: Entropic Elasticity of Permanently Folded and Permanently Unfolded Molecular SegmentsThe Journal of cell biology, 1998
- Development of stiffness precedes cross‐bridge attachment during the early tension rise in single frog muscle fibres.The Journal of Physiology, 1994
- Residual force enhancement after stretch of contracting frog single muscle fibers.The Journal of general physiology, 1982
- The sarcomere length-tension relation in skeletal muscle.The Journal of general physiology, 1978