Theory and observation of spontaneous oscillatory contractions in skeletal myofibrils

Smith, David A.; Stephenson, D. George

doi:10.1007/bf00122112

Cited by 19 publications

(12 citation statements)

References 40 publications

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“…Very similar behavior has been observed in muscles under some conditions (including low Ca 2+ concentration, which indeed means a low duty-ratio) [14]. However, other explanations which suppose that the oscillations are induced by the regulatory system are possible as well [21].…”

supporting

confidence: 74%

Force-velocity relations of a two-state crossbridge model for molecular motors

1999

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We discuss the force-velocity relations obtained in a two-state crossbridge model for molecular motors. They can be calculated analytically in two limiting cases: for a large number and for one pair of motors. The effect of the strain-dependent detachment rate on the motor characteristics is studied. It can lead to linear, myosin-like, kinesin-like and anomalous curves. In particular, we specify the conditions under which oscillatory behavior may be found.

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supporting

confidence: 74%

Force-velocity relations of a two-state crossbridge model for molecular motors

1999

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“…The time course of the sarcomere length oscillation during isotonic SPOC was simulated by Smith and Stephenson, who used a model (see figure 11(a) of Smith and Stephenson, 1994) in which the resting tension of connectin was taken into account. The model could reproduce the oscillation of sarcomeres, but the waveform was not of a sawtooth type, and the shortening velocity increased as the shortening of myofibrils proceeded.…”

Section: Synchronization Of Sarcomere Oscillations Under Isotonic Conmentioning

confidence: 99%

Synchronous behavior of spontaneous oscillations of sarcomeres in skeletal myofibrils under isotonic conditions

Yasuda¹,

Shindo²,

Ishiwata³

1996

Biophysical Journal

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An isotonic control system for studying dynamic properties of single myofibrils was developed to evaluate the change of sarcomere lengths in glycerinated skeletal myofibrils under conditions of spontaneous oscillatory contraction (SPOC) in the presence of inorganic phosphate and a high ADP-to-ATP ratio. Sarcomere length oscillated spontaneously with a peak-to-peak amplitude of about 0.5 microns under isotonic conditions in which the external loads were maintained constant at values between 1.5 x 10(4) and 3.5 x 10(4) N/m2. The shortening and yielding of sarcomeres occurred in concert, in contrast to the previously reported conditions (isomeric or auxotonic) under which the myofibrillar tension is allowed to oscillate. This synchronous SPOC appears to be at a higher level of synchrony than in the organized state of SPOC previously observed under auxotonic conditions. The period of sarcomere length oscillation did not largely depend on external load. The active tension under SPOC conditions increased as the sarcomere length increased from 2.1 to 3.2 microns, although it was still smaller than the tension under normal Ca2+ contraction (which is on the order of 10(5) N/m2). The synchronous SPOC implies that there is a mechanism for transmitting information between sarcomeres such that the state of activation of sarcomeres is affected by the state of adjacent sarcomeres. We conclude that the change of myofibrillar tension is not responsible for the SPOC of each sarcomere but that it affects the level of synchrony of sarcomere oscillations.

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“…This cannot be explained by our model. It would require either chemical signaling between adjacent sarcomeres or a gradient in one or more of the sarcomere properties (e.g., the number of myosin molecules interacting with the thin filament) as suggested by Smith and Stephenson [27].…”

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confidence: 99%

Synchronization of Active Mechanical Oscillators by an Inertial Load

Vilfan

Duke

2003

Phys. Rev. Lett.

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Motivated by the operation of myogenic (self-oscillatory) insect flight muscle, we study a model consisting of a large number of identical oscillatory contractile elements joined in a chain, whose end is attached to a damped mass-spring oscillator. When the inertial load is small, the serial coupling favors an antisynchronous state in which the extension of one oscillator is compensated by the contraction of another, in order to preserve the total length. However, a sufficiently massive load can synchronize the oscillators and can even induce oscillation in situations where isolated elements would be stable. The system has a complex phase diagram displaying quiescent, synchronous and antisynchronous phases, as well as an unusual asynchronous phase in which the total length of the chain oscillates at a different frequency from the individual active elements.

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Theory and observation of spontaneous oscillatory contractions in skeletal myofibrils

Cited by 19 publications

References 40 publications

Force-velocity relations of a two-state crossbridge model for molecular motors

Force-velocity relations of a two-state crossbridge model for molecular motors

Synchronous behavior of spontaneous oscillations of sarcomeres in skeletal myofibrils under isotonic conditions

Synchronization of Active Mechanical Oscillators by an Inertial Load

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