| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Physiology and Biophysics, University of California, Irvine, California 92697
This study tested the hypothesis that an isometric resistance-training program induces upregulation of slow myosin heavy chain (MHC) expression in a fast-twitch skeletal muscle. Thus we studied the effects of two resistance-training programs on rodent medial gastrocnemius (MG) muscle that were designed to elicit repetitive isometric contractions (10-12 per set; 4 sets per session) of different duration (8 vs. 5 s) and activation frequency (100 vs. 60 Hz) per contraction during each training session (total of 6 and 12 sessions). Results showed that both training paradigms produced significant increases in muscle weight (~11-13%) after completion of training (P < 0.05). Significant transformations in MHC expression occurred and involved specifically a decrease in the relative expression of the fast type IIb MHC and concomitant increased expression of the fast type IIx MHC. These adaptations were observed in both the "white" and "red" regions of the MG, and they occurred at both the mRNA and protein levels. These adaptations were detected after only six training sessions. Neither of the training programs produced any change in the relative expression of either the slow type I MHC or the moderately fast type IIa MHC, which can be upregulated in the red MG by chronic functional overload. These findings show that the isometric protocols used in this investigation were not sufficient to induce the hypothesized changes in the myosin heavy chain isoform expression in rodent skeletal muscle.
myosin heavy chain isoforms; messenger ribonucleic acid; resistance training; medial gastrocnemius muscle; Sprague-Dawley rats
This article has been cited by other articles:
|
|
 |
|
  F. Haddad and G. R. Adams Aging-sensitive cellular and molecular mechanisms associated with skeletal muscle hypertrophy J Appl Physiol, April 1, 2006; 100(4): 1188 - 1203. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. E. Spangenburg, T. Abraha, T. E. Childs, J. S. Pattison, and F. W. Booth Skeletal muscle IGF-binding protein-3 and -5 expressions are age, muscle, and load dependent Am J Physiol Endocrinol Metab, February 1, 2003; 284(2): E340 - E350. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Haddad and G. R. Adams Exercise Effects on Muscle Insulin Signaling and Action: Selected Contribution: Acute cellular and molecular responses to resistance exercise J Appl Physiol, July 1, 2002; 93(1): 394 - 403. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. O. Marx, W. J. Kraemer, B. C. Nindl, and L. Larsson Effects of Aging on Human Skeletal Muscle Myosin Heavy-Chain mRNA Content and Protein Isoform Expression J. Gerontol. A Biol. Sci. Med. Sci., June 1, 2002; 57(6): B232 - 238. [Abstract] [Full Text]
|
|
|
|
 |
|
 K. S. Almurshed and K. K. Grunewald Dietary Protein Does Not Affect Overloaded Skeletal Muscle in Rats J. Nutr., July 1, 2000; 130(7): 1743 - 1748. [Abstract] [Full Text]
|
|
|
|
 |
|
 S. E. Dunn, A. R. Simard, R. Bassel-Duby, R. S. Williams, and R. N. Michel Nerve Activity-dependent Modulation of Calcineurin Signaling in Adult Fast and Slow Skeletal Muscle Fibers J. Biol. Chem., November 21, 2001; 276(48): 45243 - 45254. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
