Gordon O. Matheson

Publication Details

  • P-31 NMR OF ELECTRICALLY STIMULATED RECTUS FEMORIS MUSCLE - AN INVIVO GRADED-EXERCISE MODEL MAGNETIC RESONANCE IN MEDICINE Matheson, G. O., McKenzie, D. C., Gheorghiu, D., ELLINGER, D. C., Quinney, H. A., Allen, P. S. 1992; 26 (1): 60-70

    Abstract:

    This study reports on the development of a model for studying skeletal muscle metabolism in humans using NMR spectroscopy. Graded exercise was simulated using electrical stimulation in 10 healthy, fit subjects (mean VO2max = 53 +/- 4 ml.kg-1.min-1). The effects of varying the stimulation parameters, namely, the stimulation frequency, the stimulation intensity, and the duty cycle, as well as the spectral interrogation volume, were compared using data acquired from the rectus femoris muscle. With stimulation, the inorganic phosphate to phosphocreatine concentration ratio ([P(i)]/[PCr]) and the intracellular pH both follow curvilinear relationships over the stimulation frequencies from 3 to 30 Hz, with the magnitude of the observed change related closely to stimulation intensity and duty cycle. Oxidative phosphorylation predominates at stimulation frequencies below 12 Hz, while anaerobic metabolism increases sharply above 12 Hz. Our findings show clearly the interdependence of the effects of the various stimulation parameters and emphasize the care that must be exercised in interpreting the physiological significance of the biochemical data obtained from electrical stimulation models used to study skeletal muscle metabolism.

    View details for Web of Science ID A1992JB37700006

    View details for PubMedID 1625567

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