Scientific Article
previous document  unige:10193  next document
add to browser collection
Title

Phosphocreatine hydrolysis by 31P-NMR at the onset of constant-load exercise in humans

Authors
Schenker, K.
Cerretelli, P.
Published in Journal of Applied Physiology: Respiratory, Environmental & Exercise Physiology. 1992, vol. 73, no. 4, p. 1644-1649
Abstract The kinetics of phosphocreatine (PC) breakdown in human plantar flexors at the onset of constant-load aerobic exercise was determined by high-resolution 31P-nuclear magnetic resonance spectroscopy (NMRS). The half time of the process (t1/2PC) was obtained by fitting curves (n = 13) from five subjects at various aerobic work loads for which muscle pH was not different from that at rest. Steady-state PC concentration ([PC]) was not < 70% of the resting value and was linearly related to the work load (w) ([PC] = -3.01 +/- 0.08 w + 1 (r = 0.48, 2P < 0.1)). The average t1/2PC was 16.2 s and was independent of work load. Because the half time of the muscle PC kinetics reflects the half time of the O2 uptake (MO2) kinetics (t1/2MO2), the latter is equal to that found earlier in the isolated perfused dog gastrocnemius. Whereas in the dog the above t1/2MO2 compares well with the homologous half time of the O2 uptake at the alveolar level, in humans such equivalence is found only at extremely low work loads, when the transient contribution by anaerobic glycolysis is negligible.
Keywords AdultAerobiosisExercise/ physiologyHalf-LifeHumansHydrogen-Ion ConcentrationHydrolysisLeg/anatomy & histology/physiologyMagnetic Resonance ImagingMagnetic Resonance SpectroscopyMiddle AgedOxygen Consumption/physiologyPerfusionPhosphocreatine/ metabolism
Stable URL http://archive-ouverte.unige.ch/unige:10193
Full text
Article - document accessible for UNIGE members only Limited access to UNIGE
Other version: http://jap.physiology.org/cgi/reprint/73/4/1644.pdf
Identifiers
PMID: 1447115
155 hits and 0 download since 2010-08-06
Update
Export document
Format :
Citation style :