Effect of muscle action and metabolic strain on oxidative metabolic responses in human skeletal muscle.

Content Provider	Semantic Scholar
Author	Balaban, Robert S.
Copyright Year	1999
Abstract	A recent report suggests that differences in aerobic capacity exist between concentric and eccentric muscle action in human muscle (T. W. Ryschon, M. D. Fowler, R. E. Wysong, A. R. Anthony, and R. S. Balaban. J. Appl. Physiol. 83: 867-874, 1997). This study compared oxidative response, in the form of phosphocreatine (PCr) resynthesis rates, with matched levels of metabolic strain (i.e., changes in ADP concentration or the free energy of ATP hydrolysis) in tibialis anterior muscle exercised with either muscle action in vivo (n = 7 subjects). Exercise was controlled and metabolic strain measured by a dynamometer and (31)P-magnetic resonance spectroscopy, respectively. Metabolic strain was varied to bring cytosolic ADP concentration up to 55 microM or decrease the free energy of ATP hydrolysis to -55 kJ/mol with no change in cytoplasmic pH. PCr resynthesis rates after exercise ranged from 31.9 to 462.5 and from 21.4 to 405.4 micromol PCr/s for concentric and eccentric action, respectively. PCr resynthesis rates as a function of metabolic strain were not significantly different between muscle actions (P > 0.40), suggesting that oxidative capacity is dependent on metabolic strain, not muscle action. Pooled data were found to more closely conform to previous biochemical measurements when a term for increasing oxidative capacity with metabolic strain was added to models of respiratory control.
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://jap.physiology.org/content/jap/87/5/1768.full.pdf
PubMed reference number	10562621v1
Volume Number	87
Issue Number	5
Journal	Journal of applied physiology
Language	English
Access Restriction	Open
Subject Keyword	APPL1 gene ATP Citrate (pro-S)-Lyase ATP Hydrolysis Adenosine Diphosphate Adenosine Triphosphate Cell Respiration DUOXA1 gene Metabolic Process, Cellular Micromole Phosphocreatine Polymerase Chain Reaction Skeletal muscle structure Tibialis anterior muscle structure free energy kilojoule (kJ)
Content Type	Text
Resource Type	Article