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Discrepency Between Evidence and Theory of Myoglobin S02 in Work

  • John W. Severinghaus
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 388)

Abstract

Gayeski, Federspiel and Honig [11] showed that myoglobin Po2 during maximum electrically stimulated exercise in dog gracilis muscle fell as low as 1 torr, but usually was limited to 3–5 torr, and was remarkably uniform, suggesting that much of the diffusion gradient for 02 was between red cells and myocytes. Myoglobin is 50% saturated at about 4 torr, pH = 7, and has no Bohr effect. Its dissociation curve is a single exponential. In recent experiments Richardson et al. [2], using 1H MRS quantification of the quadriceps myoglobin.signal with one leg exercise in human volunteers, indicated that SMb02 fell with mild exercise (25% Vo2max) to about 50%, but remained at that level at four higher work levels (approaching Vo2max).

Keywords

Diffusion Gradient Bohr Effect Work Increase Capillary Recruitment Mild Exercise 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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    Gayeski, T. E. J., W. J. Federspiel, and C. R. Honig. A graphical analysis of the influence of red cell transit time, carrier-free layer thickness, and intracellular P02 on blood-tissue 02 transport. Adv. Exp. Me£L Biol. 222: 25–35, 1988.Google Scholar
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    Richardson R. S., E. A. Noyszewski, K F. Kendrick J. S. Leigh, R D. Wagner. Evidence for a substantial po2 gradient from blood to myoglobin during maximal quadriceps exercise in normal man. Clin Res. 42:2:254AApr 1994.Google Scholar
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    Roca, J., A. G. Agusti, A. Alonso, D. C. Poole, C. Viegas, J. A. Barbera, R. Rodriguez-Rouiin, A. Ferrer, P. D. Wagner. Effects of training on muscle 02 transport at V02max. J. Appi Physiol 73:1067–1076,1992.Google Scholar
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    Severinghaus, J.W Exercise 02 transport model assuming zero cytochrome PO2 at VO2max. J Appi Physiol 77:671–678, 1994.Google Scholar
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    Wasserman, K Coupling of external to cellular respiration during exercise: the wisdom of the body revisited. Am J. Physiol 266 (Endrocrinol. Metab 29): E519–E539, 1994.PubMedGoogle Scholar

Copyright information

© Plenum Press, New York 1996

Authors and Affiliations

  • John W. Severinghaus
    • 1
    • 2
  1. 1.University of California Medical SchoolSan FranciscoUSA
  2. 2.RossUSA

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