|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Journal of Experimental Biology, Vol 200, Issue 3 495-501, Copyright © 1997 by Company of Biologists
JOURNAL ARTICLES |
F Lou, N Curtin and R Woledge
The energetic cost of activation was measured during an isometric tetanus of white muscle fibres from the dogfish Scyliorhinus canicula. The total heat production by the fibres was taken as a measure of the total energetic cost. This energy consists of two parts. One is due to crossbridge interaction which produces isometric force, and this part varies linearly with the degree of filament overlap in the fibres. The other part of the energy is that associated with activation of the crossbridges by Ca2+, mainly with uptake of Ca2+ into the sarcoplasmic reticulum by the ATP-driven Ca2+ pump. Total heat production was measured at various degrees of filament overlap beyond the optimum for force development. Extrapolation of heat versus force production data to evaluate the heat remaining at zero force gave a value of 34±5 % (mean ± s.e.m., N=24) for activation heat as a percentage of total heat production in a 2.0 s isometric tetanus. Values for 0.4 and 1.0 s of stimulation were similar. Comparison with values in the literature shows that the energetic cost of activation in dogfish muscle is very similar to that of frog skeletal muscle and it cannot explain the lower maximum efficiency of dogfish muscle compared with frog muscle. The proportion of energy for activation (Ca2+ turnover) is similar to that expected from a simple model in which Ca2+ turnover was varied to minimize the total energy cost for a contraction plus relaxation cycle.
This article has been cited by other articles:
|
|
 |
|
  S.-J. Zhang, D. C. Andersson, M. E. Sandstrom, H. Westerblad, and A. Katz Cross bridges account for only 20% of total ATP consumption during submaximal isometric contraction in mouse fast-twitch skeletal muscle Am J Physiol Cell Physiol, July 1, 2006; 291(1): C147 - C154. [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]
|
|
|
|
|
|
T. G. West, N. A. Curtin, M. A. Ferenczi, Z.-H. He, Y.-B. Sun, M. Irving, and R. C. Woledge Actomyosin energy turnover declines while force remains constant during isometric muscle contraction J. Physiol., February 15, 2004; 555(1): 27 - 43. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. L. Darques, D Bendahan, M Roussel, B Giannesini, F Tagliarini, Y Le Fur, P. J. Cozzone, and Y Jammes Combined in situ analysis of metabolic and myoelectrical changes associated with electrically induced fatigue J Appl Physiol, October 1, 2003; 95(4): 1476 - 1484. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Abbate, C. J. De Ruiter, C. Offringa, A. J. Sargeant, and A. De Haan In situ rat fast skeletal muscle is more efficient at submaximal than at maximal activation levels J Appl Physiol, May 1, 2002; 92(5): 2089 - 2096. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. H. Marden and L. R. Allen Molecules, muscles, and machines: Universal performance characteristics of motors PNAS, April 2, 2002; 99(7): 4161 - 4166. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Gustafson, G. Egrie, and S. Reichenbach Relative metabolic utilization of in situ rabbit soleus muscle: thermistor-based measurements and model J. Exp. Biol., January 12, 2000; 203(23): 3667 - 3674. [Abstract] [PDF]
|
|
|
|
|
|
J. H. Marden and L. R. Allen Molecules, muscles, and machines: Universal performance characteristics of motors PNAS, April 2, 2002; 99(7): 4161 - 4166. [Abstract] [Full Text] [PDF]
|
|
