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

The time course of the contractile process was investigated in the presence of AR-L 115BS, a twitch potentiator which is thought to increase the rate of the Ca2+ binding by troponin and to improve the Ca2+ mobilization from the sarcoplasmic reticulum.AR-L 115BS increased markedly the rate of development of the force-velocity (T-V) relation and of the isometric tetanic tension. The effect on the rate of development of theT-V relation was however substantially more intense than that on the speed of rise of tetanic tension, thus reducing considerably the isometric tension level at which theT-V relation attained its final characteristics. The velocity of shortening under zero load and the degree of curvature of theT-V relation were not affected by AR-L 115BS.These findings support the view that the development of theT-V relation and the rise of the isometric tetanic tension measure the time course of two different processes.

[1]  F. Julian,et al.  Variation of muscle stiffness with force at increasing speeds of shortening , 1975, The Journal of general physiology.

[2]  S. Ebashi,et al.  Regulation of muscle contraction. , 1980, Cell and muscle motility.

[3]  H. Weisenberger,et al.  Studies on the mechanism of the positive-inotropic action of AR-L 115 BS, a new cardiotonic drug. , 1981, Arzneimittel-Forschung.

[4]  K. Edman,et al.  Non-hyperbolic force-velocity relationship in single muscle fibres. , 1976, Acta physiologica Scandinavica.

[5]  V. Lombardi,et al.  Force‐velocity relation in normal and nitrate‐treated frog single muscle fibres during rise of tension in an isometric tetanus. , 1978, The Journal of physiology.

[6]  H. Huxley.  The structural basis of contraction and regulation in skeletal muscle. , 1975, Kaibogaku zasshi. Journal of anatomy.

[7]  Huxley Af,et al.  Mechanical properties of the cross-bridges of frog striated muscle. , 1971 .

[8]  G. Piazzesi,et al.  The development of the force-velocity relation in normal and dantrolene-treated frog single muscle fibres , 1983, Journal of Muscle Research & Cell Motility.

[9]  A. Huxley,et al.  Mechanical Transients and the Origin of Muscular Force , 1973 .

[10]  R. Solaro,et al.  Stimulation of Ca++ Binding and ATPase Activity of Dog Cardiac Myofibrils by AR‐L 115BS, a Novel Cardiotonic Agent , 1982, Circulation research.

[11]  G. Piazzesi,et al.  Development of activation and rise of tension in an isometric tetanus , 1979, Pflügers Archiv.

[12]  P. J. Griffiths,et al.  Muscular contraction: kinetics of crossbridge attachment studied by high-frequency stiffness measurements. , 1982, Science.

[13]  L. Teichholz,et al.  The relation between calcium and contraction kinetics in skinned muscle fibres , 1970, The Journal of physiology.

[14]  L. Teichholz,et al.  Ionic Strength and the Contraction Kinetics of Skinned Muscle Fibers , 1974, The Journal of general physiology.

[15]  J. Rüegg,et al.  Activating effects of AR-L 115 BS on the Ca2+ sensitive force, stiffness and unloaded shortening velocity (Vmax) in isolated contractile structures from mammalian heart muscle. , 1981, Arzneimittel-Forschung.

[16]  S. Ebashi.  The Croonian Lecture, 1979: Regulation of muscle contraction , 1980, Proceedings of the Royal Society of London. Series B. Biological Sciences.

[17]  E. Gorter,et al.  Muscular Contraction , 1926, Nature.

[18]  D. Brutsaert,et al.  Effects of AR‐L115 on Contraction and Relaxation of Isolated Mammalian Cardiac Muscle , 1982, Journal of cardiovascular pharmacology.

[19]  T. Wieland,et al.  Molecular Basis of Motility , 1976, 26. Colloquium der Gesellschaft für Biologische Chemie 10.–12. April 1975 in Mosbach/Baden.

[20]  F. Julian.  Activation in a skeletal muscle contraction model with a modification for insect fibrillar muscle. , 1969, Biophysical journal.

[21]  V. Lombardi,et al.  Development of force-velocity relation, stiffness and isometric tension in frog single muscle fibres , 1983, Journal of Muscle Research & Cell Motility.

[22]  A. Huxley.  Muscle structure and theories of contraction. , 1957, Progress in biophysics and biophysical chemistry.

[23]  A. Huxley.  Muscular contraction. Review lecture , 1974 .

[24]  S Ebashi,et al.  Control of muscle contraction , 1969, Quarterly Reviews of Biophysics.

[25]  A. Huxley,et al.  Tension responses to sudden length change in stimulated frog muscle fibres near slack length , 1977, The Journal of physiology.

[26]  V. Lombardi,et al.  Force‐velocity relation in deuterium oxide‐treated frog single muscle fibres during the rise of tension in an isometric tetanus. , 1981, The Journal of physiology.

[27]  A. Huxley,et al.  Mechanical properties of the cross-bridges of frog striated muscle. , 1971, The Journal of physiology.

[28]  F. Julian,et al.  Regulation of Force and Speed of Shortening in Muscle Contraction , 1973 .