Metabolic transient studies by NMR.
The time course of phosphocreatine (PC) hydrolysis in humans was measured by 31P-NMR spectroscopy (31P-NMRS) with a time resolution of 10.8 s in the gastrocnemius muscle and a relationship between muscle O2 consumption (VO2) and [PC] was derived from a bioenergetic model. This allowed a direct estimate of the half-time of the intracellular VO2 kinetics (t1/2 VO2) of the contracting human gastrocnemius in aerobic conditions. t1/2 VO2 was found to be approximately 16 s and independent of the work load. This value corresponds to the shortest t1/2 VO2 determined at the mouth of the subject in the absence of lactate accumulation in the rest to work transient. t1/2 VO2 may now be assessed in man at low muscle temperatures. To this aim a procedure was developed allowing corrections of the 31P-NMR spectra based on the muscle temperature profiles obtained by a simultaneously acquired proton image.
Binzoni
T
T
Dépt. de Physiologie, CMU, Genève, Switzerland.
Ferretti
G
G
Schenker
K
K
Barbalat
F
F
Hiltbrand
E
E
Cerretelli
P
P
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D001831:Body Temperature / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology; D006801:Humans; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D009132:Muscles / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D010725:Phosphocreatine / Q000378:metabolism
D010725:Phosphocreatine; D000255:Adenosine Triphosphate