| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 The Randall Centre, King's College London, London SE1 1UL, UK
The time course of isometric force development following photolytic release of ATP in the presence of Ca2+ was characterized in single skinned fibres from rabbit psoas muscle. Pre-photolysis force was minimized using apyrase to remove contaminating ATP and ADP. After the initial force rise induced by ATP release, a rapid shortening ramp terminated by a step stretch to the original length was imposed, and the time course of the subsequent force redevelopment was again characterized. Force development after ATP release was accurately described by a lag phase followed by one or two exponential components. At 20°C, the lag was 5.6 ± 0.4 ms (S.E.M., n = 11), and the force rise was well fitted by a single exponential with rate constant 71 ± 4 s–1. Force redevelopment after shortening–restretch began from about half the plateau force level, and its single-exponential rate constant was 68 ± 3 s–1, very similar to that following ATP release. When fibres were activated by the addition of Ca2+ in ATP-containing solution, force developed more slowly, and the rate constant for force redevelopment following shortening–restretch reached a maximum value of 38 ± 4 s–1 (n = 6) after about 6 s of activation. This lower value may be associated with progressive sarcomere disorder at elevated temperature. Force development following ATP release was much slower at 5°C than at 20°C. The rate constant of a single-exponential fit to the force rise was 4.3 ± 0.4 s–1 (n = 22), and this was again similar to that after shortening–restretch in the same activation at this temperature, 3.8 ± 0.2 s–1. We conclude that force development after ATP release and shortening–restretch are controlled by the same steps in the actin–myosin ATPase cycle. The present results and much previous work on mechanical–chemical coupling in muscle can be explained by a kinetic scheme in which force is generated by a rapid conformational change bracketed by two biochemical steps with similar rate constants – ATP hydrolysis and the release of inorganic phosphate – both of which combine to control the rate of force development.
(Received 8 November 2004;
accepted after revision 9 December 2004;
first published online 20 December 2004)
Corresponding author J. Sleep: Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK. Email: john.sleep{at}kcl.ac.uk
This article has been cited by other articles:
|
|
 |
|
  M. Caremani, J. Dantzig, Y. E. Goldman, V. Lombardi, and M. Linari Effect of Inorganic Phosphate on the Force and Number of Myosin Cross-Bridges During the Isometric Contraction of Permeabilized Muscle Fibers from Rabbit Psoas Biophys. J., December 15, 2008; 95(12): 5798 - 5808. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. S. Campbell Filament Compliance Effects Can Explain Tension Overshoots during Force Development Biophys. J., December 1, 2006; 91(11): 4102 - 4109. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Burton, R. M. Simmons, J. Sleep, R. M. Simmons, K. Burton, and D. A. Smith Kinetics of force recovery following length changes in active skinned single fibres from rabbit psoas muscle: with an Appendix: Analysis and modelling of the late recovery phase J. Physiol., June 1, 2006; 573(2): 305 - 328. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. B. Siththanandan, J. L. Donnelly, and M. A. Ferenczi Effect of Strain on Actomyosin Kinetics in Isometric Muscle Fibers Biophys. J., May 15, 2006; 90(10): 3653 - 3665. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. C. Hopflinger, O. Andruchova, O. Andruchov, H. Grassberger, and S. Galler Effect of pH on the rate of myosin head detachment in molluscan catch muscle: are myosin heads involved in the catch state? J. Exp. Biol., February 15, 2006; 209(4): 668 - 676. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. S. Campbell Tension Recovery in Permeabilized Rat Soleus Muscle Fibers after Rapid Shortening and Restretch Biophys. J., February 15, 2006; 90(4): 1288 - 1294. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Sleep, A. Lewalle, and D. Smith Reconciling the working strokes of a single head of skeletal muscle myosin estimated from laser-trap experiments and crystal structures PNAS, January 31, 2006; 103(5): 1278 - 1282. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. G West, M. A Ferenczi, R. C Woledge, and N. A Curtin Influence of ionic strength on the time course of force development and phosphate release by dogfish muscle fibres J. Physiol., September 15, 2005; 567(3): 989 - 1000. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Burton, H. White, and J. Sleep Kinetics of muscle contraction and actomyosin NTP hydrolysis from rabbit using a series of metal-nucleotide substrates J. Physiol., March 15, 2005; 563(3): 689 - 711. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
