Metabolic Modulation of Muscle Fiber Properties Unrelated to Mechanical Stimuli

DOI Web Site PubMed 7 Citations 73 References
  • Ohira Yoshinobu
    School of Health and Sport Sciences, Osaka University Graduate School of Medicine, Osaka University
  • Kawano Fuminori
    School of Health and Sport Sciences, Osaka University Graduate School of Medicine, Osaka University
  • Roy Roland R.
    Brain Research Institute, University of California, Los Angeles
  • Edgerton V. Reggie
    Brain Research Institute, University of California, Los Angeles Department of Physiological Science, University of California, Los Angeles

Search this article

Description

The effects of chronically increasing (creatine-fed) or decreasing (β-guanidinopropionic acid [β-GPA]–fed) high-energy phosphates for up to 8 weeks on daily voluntary activity levels, swimming endurance capacity, electromyogram (EMG) activity, and the morphological and metabolic properties of single fibers in the soleus and extensor digitorum longus (EDL) muscles in young rats were determined. High-energy phosphate, voluntary activity, and soleus-integrated EMG levels were lower in β-GPA–fed rats than in control rats. Endurance capacity was higher at a relatively low intensity of swimming and lower at a relatively high intensity in β-GPA–fed rats than in control rats. Muscle mass and fiber size were smaller, and the percentage of slow fibers was higher in the soleus and EDL of β-GPA–fed rats than in control rats. Succinate dehydrogenase activity was higher in both the fast and slow fibers of the EDL of β-GPA–fed rats than in control rats. Thus, a reduction in high-energy phosphates transformed some fast fibers toward a slow phenotype. Creatine supplementation had minimal effects: The only significant change was an increase in α-glycerophosphate dehydrogenase activity in the fast fibers of the EDL. These results indicate that the metabolic environment of a muscle fiber can influence the prominence of a given muscle fiber independent of the activity level of muscle.<br>

Journal

Citations (7)*help

See more

References(73)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top