|
|
||||||||
1 Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hung Hom, Kowloon; 2 Department of Physiology, University of Hong Kong, Hong Kong, China; and 3 Institute for Biomedical Research and Department of Physiology, University of Sydney F13, Sydney NSW 2006, Australia
The effect of eccentric contractions on intracellular Na+ concentration ([Na+]i) and its distribution were examined in isolated rat and mouse muscle fiber bundles. [Na+]i was measured with either Na+-binding benzofuran isophthalate or sodium green. Ten isometric contractions had no significant effect on force (measured after 5 min of recovery) and caused no significant change in the resting [Na+]i (7.2 ± 0.5 mM). In contrast 10 eccentric contractions (40% stretch at 4 muscle lengths/s) reduced developed force at 100 Hz to 45 ± 3% of control and increased [Na+]i to 16.3 ± 1.6 mM (n = 6; P < 0.001). The rise of [Na+]i occurred over 1-2 min and showed only minimal recovery after 30 min. Confocal images of the distribution of [Na+]i showed a spatially uniform distribution both at rest and after eccentric contractions. Gd3+ (20 µM) had no effect on resting [Na+]i or control tetanic force but prevented the rise of [Na+]i and reduced the force deficit after eccentric damage. These data suggest that Na+ entry after eccentric contractions may occur principally through stretch-sensitive channels.
muscle; eccentric damage; intracellular sodium; gadolinium; stretch-sensitive channels
This article has been cited by other articles:
![]() |
S. P. Cairns and M. I. Lindinger Do multiple ionic interactions contribute to skeletal muscle fatigue? J. Physiol., September 1, 2008; 586(17): 4039 - 4054. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. E. Spangenburg and T. A. McBride Inhibition of stretch-activated channels during eccentric muscle contraction attenuates p70S6K activation J Appl Physiol, January 1, 2006; 100(1): 129 - 135. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. G Allen, N. P Whitehead, and E. W Yeung Mechanisms of stretch-induced muscle damage in normal and dystrophic muscle: role of ionic changes J. Physiol., September 15, 2005; 567(3): 723 - 735. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. W. Yeung, N. P. Whitehead, T. M. Suchyna, P. A. Gottlieb, F. Sachs, and D. G. Allen Effects of stretch-activated channel blockers on [Ca2+]i and muscle damage in the mdx mouse J. Physiol., January 15, 2005; 562(2): 367 - 380. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Parikh, D. L. Morgan, J. E. Gregory, and U. Proske Low-frequency depression of tension in the cat gastrocnemius muscle after eccentric exercise J Appl Physiol, October 1, 2004; 97(4): 1195 - 1202. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. W Yeung, S. I Head, and D. G Allen Gadolinium reduces short-term stretch-induced muscle damage in isolated mdx mouse muscle fibres J. Physiol., October 15, 2003; 552(2): 449 - 458. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |