Affiliation:
1. Aix-Marseille Univ, Centre National de la Recherche Scientifique, Centre de Résonance Magnétique Biologique et Médicale, Marseille, France
2. Biochemistry and Molecular Medicine, University of California Davis, Davis, California
Abstract
Muscle contraction requires the physiology to adapt rapidly to meet the surge in energy demand. To investigate the shift in metabolic control, especially between oxygen and metabolism, researchers often depend on near-infrared spectroscopy (NIRS) to measure noninvasively the tissue O2. Because NIRS detects the overlapping myoglobin (Mb) and hemoglobin (Hb) signals in muscle, interpreting the data as an index of cellular or vascular O2 requires deconvoluting the relative contribution. Currently, many in the NIRS field ascribe the signal to Hb. In contrast, 1H NMR has only detected the Mb signal in contracting muscle, and comparative NIRS and NMR experiments indicate a predominant Mb contribution. The present study has examined the question of the NIRS signal origin by measuring simultaneously the 1H NMR, 31P NMR, and NIRS signals in finger flexor muscles during the transition from rest to contraction, recovery, ischemia, and reperfusion. The experiment results confirm a predominant Mb contribution to the NIRS signal from muscle. Given the NMR and NIRS corroborated changes in the intracellular O2, the analysis shows that at the onset of muscle contraction, O2 declines immediately and reaches new steady states as contraction intensity rises. Moreover, lactate formation increases even under quite aerobic condition.
Funder
France Berkeley Fund
Burroughs Wellcome Fund (BWF)
Centre National de Recherche Scientifique
France Life Imaging Network
Publisher
American Physiological Society
Subject
Physiology (medical),Physiology
Cited by
35 articles.
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