Passive force enhancement in single myofibrils

Joumaa, Venus; Rassier, Dilson E.; Leonard, Tim

doi:10.1007/s00424-007-0287-2

Cited by 68 publications

(64 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Finally, a study performed with permeabilized fibres from mammalian muscles, in which extracellular structures and events associated with Ca 2þ release are not involved in stiffness or force measurements, confirmed the presence of the static tension, which was directly associated with the residual force enhancement [16]. In a few studies, the static tension is observed even a few seconds after activation stops [55,62,63], although the nature of this persistent passive force enhancement, is unknown, and it is not always observed.…”

Section: Mechanisms Of Force Enhancementmentioning

confidence: 78%

The mechanisms of the residual force enhancement after stretch of skeletal muscle: non-uniformity in half-sarcomeres and stiffness of titin

Rassier

2012

Proc. R. Soc. B.

View full text Add to dashboard Cite

When activated skeletal muscles are stretched, the force increases significantly. After the stretch, the force decreases and reaches a steady-state level that is higher than the force produced at the corresponding length during purely isometric contractions. This phenomenon, referred to as residual force enhancement, has been observed for more than 50 years, but the mechanism remains elusive, generating considerable debate in the literature. This paper reviews studies performed with single muscle fibres, myofibrils and sarcomeres to investigate the mechanisms of the stretch-induced force enhancement. First, the paper summarizes the characteristics of force enhancement and early hypotheses associated with non-uniformity of sarcomere length. Then, it reviews new evidence suggesting that force enhancement can also be associated with sarcomeric structures. Finally, this paper proposes that force enhancement is caused by: (i) half-sarcomere non-uniformities that will affect the levels of passive forces and overlap between myosin and actin filaments, and (ii) a Ca 2þ -induced stiffness of titin molecules. These mechanisms are compatible with most observations in the literature, and can be tested directly with emerging technologies in the near future.

show abstract

Section: Mechanisms Of Force Enhancementmentioning

confidence: 78%

The mechanisms of the residual force enhancement after stretch of skeletal muscle: non-uniformity in half-sarcomeres and stiffness of titin

Rassier

2012

Proc. R. Soc. B.

View full text Add to dashboard Cite

show abstract

“…On the day of the experiment, the muscle strips were removed from the freezer, homogenized, and then placed in a lowcalcium relaxing solution containing ATP at 4°C. High-calcium (pCa 3.5) and low-calcium solutions (pCa 8) at 4°C were used for the activation-deactivation sequences (18). Specimen length was controlled using a drawn glass pipette attached to a piezotube motor (Boston Piezo-Optics, Bellingham, MA).…”

Section: Methodsmentioning

confidence: 99%

Force enhancement following stretch in a single sarcomere

Leonard

DuVall

Herzog

2010

American Journal of Physiology-Cell Physiology

Self Cite

110

105

View full text Add to dashboard Cite

It has been accepted for half a century that, for a given level of activation, the steady-state isometric force of a muscle sarcomere depends exclusively on the amount of overlap between the contractile filaments actin and myosin, or equivalently sarcomere length (Gordon AM et al., J Physiol 184: 170 -192, 1966). Moreover, according to the generally accepted paradigm of muscle contraction, the cross-bridge theory (Huxley AF, Prog Biophys Biophys Chem 7: 255-318, 1957), this steady-state isometric sarcomere force is independent of the muscle's contractile history (Huxley AF, Prog Biophys Biophys Chem 7: 255-318, 1957; Walcott S and Herzog W, Math Biosci 216: 172-186, 2008); i.e., it is independent of whether a muscle is held at a constant length before and during the contraction or whether the muscle is shortened or lengthened to the same constant length. This, however, is not the case, as muscles and single fibers that are stretched show greatly increased steady-state isometric forces compared with preparations that are held at a constant length (Abbott BC and Aubert XM,

show abstract

“…Furthermore, passive force after deactivation of an actively stretched muscle is higher than the force produced after a purely passive stretch or after deactivation from an isometric contraction at the corresponding length (13,14). This so-called "passive force enhancement" was first observed in the cat soleus muscle (13), and then in human muscle preparations (19), single fibers (18,28,30), and recently in single myofibrils (16).…”

mentioning

confidence: 98%

The origin of passive force enhancement in skeletal muscle

Joumaa

Rassier²,

Leonard³

et al. 2008

American Journal of Physiology-Cell Physiology

Self Cite

119

117

View full text Add to dashboard Cite

The aim of the present study was to test whether titin is a calcium-dependent spring and whether it is the source of the passive force enhancement observed in muscle and single fiber preparations. We measured passive force enhancement in troponin C (TnC)-depleted myofibrils in which active force production was completely eliminated. The TnC-depleted construct allowed for the investigation of the effect of calcium concentration on passive force, without the confounding effects of actin-myosin cross-bridge formation and active force production. Passive forces in TnC-depleted myofibrils ( n = 6) were 35.0 ± 2.9 nN/ μm2 when stretched to an average sarcomere length of 3.4 μm in a solution with low calcium concentration (pCa 8.0). Passive forces in the same myofibrils increased by 25% to 30% when stretches were performed in a solution with high calcium concentration (pCa 3.5). Since it is well accepted that titin is the primary source for passive force in rabbit psoas myofibrils and since the increase in passive force in TnC-depleted myofibrils was abolished after trypsin treatment, our results suggest that increasing calcium concentration is associated with increased titin stiffness. However, this calcium-induced titin stiffness accounted for only ∼25% of the passive force enhancement observed in intact myofibrils. Therefore, ∼75% of the normally occurring passive force enhancement remains unexplained. The findings of the present study suggest that passive force enhancement is partly caused by a calcium-induced increase in titin stiffness but also requires cross-bridge formation and/or active force production for full manifestation.

show abstract

Passive force enhancement in single myofibrils

Cited by 68 publications

References 31 publications

The mechanisms of the residual force enhancement after stretch of skeletal muscle: non-uniformity in half-sarcomeres and stiffness of titin

The mechanisms of the residual force enhancement after stretch of skeletal muscle: non-uniformity in half-sarcomeres and stiffness of titin

Force enhancement following stretch in a single sarcomere

The origin of passive force enhancement in skeletal muscle

Contact Info

Product

Resources

About