Development of force-velocity relation and rise of isometric tetanic tension measure the time course of different processes

Cecchi, Giovanni; Lombardi, Vincenzo; Menchetti, G

doi:10.1007/bf00584342

Cited by 11 publications

(2 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another obvious and important consequence of the velocity-dependent deactivation described in the present paper is that, unlike the views of various investigators (Cecchi et al 1978(Cecchi et al , 1981(Cecchi et al , 1984, it seems that the characteristics of an instantaneous T-V relation at a time during the rise of an isometric tetanus cannot be taken as an accurate measure of the activation level at that time, or in other words the course of development of T during the tetanus rise is not a fully reliable measure of the course of development of activation.…”

Section: Discussioncontrasting

confidence: 57%

“…As to the nature of these factors in terms of a cross-bridge model of activation (Huxley, 1957;Julian, 1969;Julian & Sollins, 1973) it could be assumed that in a tetanic contraction the rate of development of activation is controlled not only by the rate of release of Ca2+ Cecchi, Lombardi & Menchetti, 1984), but also by the velocity at which the muscle fibres are allowed to shorten, or in other words, by the actual number of attached cross-bridges. Actually, in accordance with the predictions ofthe cross-bridge model of Huxley (1957), shortening has been shown to reduce both the number of attached cross-bridges and the average time they spend attached, and, in addition, the amounts of both effects are related to the shortening velocity (Fenn, 1923;Julian & Sollins, 1975;Julian & Morgan, 1981;Homsher, Yamada, Wallner & Tsai, 1984;Ford, Huxley & Simmons, 1985).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

A velocity‐dependent shortening depression in the development of the force‐velocity relation in frog muscle fibres.

Colomo¹,

Lombardi²,

Piazzesi³

1986

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. During the onset of activation in isolated frog muscle fibres the development of the force-velocity (T-V) relation was determined by imposing single and double ramp releases. The experiments were performed at 35-6 0C or 19-22 TC and at a starting sarcomere length of about 2-25 ,um.2. A velocity-and time-dependent shortening deactivation was shown to exist during the development of contraction. It was found that, early during the tetanus rise, at submaximal levels of activation, the values of T (the steady force exerted by the muscle fibres at any velocity of shortening V lower than V0) were significantly affected by previous conditioning shortening. Conditioning shortening at lower speeds led to potentiation of T and, at higher speeds, to depression. Both these effects were independent of the amount of shortening and, in addition, were not present at the tetanus plateau.3. At each given time or isometric tension throughout the tetanus rise the values of T, normalized for those determined at the same velocities at the tetanus plateau, were found to be inversely correlated with the actual velocities of shortening. The slope of this relation (a measure of the velocity-dependent shortening deactivation) decreased exponentially with time, attaining, in six fibres at low temperature, 10 % of its initial value within 26-73 ms.4. The results may be explained in terms of a cross-bridge model of contraction by assuming that the rate of development of activation is controlled by the rate of release of the Ca2+ as well as by the velocity at which the muscle fibres are allowed to shorten and in turn by the actual number of attached cross-bridges.

show abstract

Section: Discussioncontrasting

confidence: 57%

Section: Discussionmentioning

confidence: 99%

A velocity‐dependent shortening depression in the development of the force‐velocity relation in frog muscle fibres.

Colomo¹,

Lombardi²,

Piazzesi³

1986

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

Hill-Based Muscle Models: A Systems Engineering Perspective

Winters¹

1990

Multiple Muscle Systems

296

167

View full text Add to dashboard Cite

Effects of amrinone on shortening velocity and force development in skinned skeletal muscle fibres

Aottinelli

Cappelli

Mörner

et al. 1993

J Muscle Res Cell Motil

View full text Add to dashboard Cite

The effects of amrinone were studied on single skinned fibres isolated from rat hindlimb muscles. In each fibre a force-velocity relation was determined during maximal calcium activation (pCa = 4.45) in control conditions and in the presence of amrinone. The MgATP concentration was 3.93 mM, close to the physiological value. After the experiment the fibre was classified as fast or slow on the basis of its reactivity with anti-myosin monoclonal antibodies. In fast fibres amrinone (3 mM) potentiated isometric tension (Po) by 13.8 +/- 2.9% (n = 13), reduced maximum shortening velocity (Vmax) by 32.6 +/- 3.2% and the curvature of the force-velocity relation (a/Po) was increased by 98.9 +/- 46.0%. All these effects were less pronounced in slow fibres, where Vmax was reduced only by 11.4 +/- 3.6 (n = 16). The effects of amrinone (0.3-6 mM) on the ATPase activity of myofibrils and myosin prepared from fast (tibialis anterior) and slow (soleus) rat skeletal muscles were studied. Amrinone was found to depress Ca-Mg dependent ATPase activity of myofibrillar preparations of the tibialis anterior (up to 16.6 +/- 2%) and, to a lesser extent, of the soleus (up to 7.2 +/- 1.2%). On the contrary, Ca-stimulated myosin ATPase activity was significantly increased by amrinone in myosin preparations from the tibialis anterior. Experiments were carried out to test whether amrinone (3 mM) might affect the sensitivity of the contractile system to MgATP concentration ([MgATP]). The results obtained showed that (1) the [MgATP] value at which isometric tension reached its maximum was shifted by amrinone from 0.1 mM to 0.3 mM, (2) the slope of the negative relation between [MgATP] and a/Po was made more steep by amrinone, and (3) the Km of the hyperbolic relation between [MgATP] and Vmax was increased from 0.39 to 1.71 mM by amrinone, thus indicating a reduced affinity of myosin for MgATP. These results are in accordance with the hypothesis that amrinone exerts a direct effect on the contractile mechanism.

show abstract

Development of force-velocity relation and rise of isometric tetanic tension measure the time course of different processes

Cited by 11 publications

References 22 publications

A velocity‐dependent shortening depression in the development of the force‐velocity relation in frog muscle fibres.

A velocity‐dependent shortening depression in the development of the force‐velocity relation in frog muscle fibres.

Hill-Based Muscle Models: A Systems Engineering Perspective

Effects of amrinone on shortening velocity and force development in skinned skeletal muscle fibres

Contact Info

Product

Resources

About