Spatial heterogeneity of metabolism in skeletal muscle in vivo studied by 31P-NMR spectroscopy.
Phase-modulated rotating-frame imaging, a localization technique for phosphorus nuclear magnetic resonance spectroscopy, has been applied to obtain information on heterogeneity of phosphorus-containing metabolites in skeletal muscle of the rat in vivo. The distal muscles of the rat hindlimb have been studied at rest and during steady-state isometric twitch contraction; the use of a transmitter surface coil and an electrically isolated, orthogonal receiver Helmholtz coil ensure accurate spatial assignment (1 mm resolution). At rest, intracellular pH was higher and PCr/(PCr + Pi) was lower in deeper muscles compared with superficial muscle of the distal hindlimb. Upon steady-state stimulation, the relatively more alkaline pH of deep muscle was maintained, whereas greater changes in PCr/(PCr + Pi) and Pi/ATP occurred in the superficial muscle layer. This method allows rapid (75 min for each spectral image) acquisition of quantitative information on metabolic heterogeneity in vivo.
Challiss
R A
RA
Department of Biochemistry, University of Oxford, United Kingdom.
Blackledge
M J
MJ
Radda
G K
GK
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004558:Electric Stimulation; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009132:Muscles / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012146:Rest; D012584:Sciatic Nerve / Q000502:physiology
D010725:Phosphocreatine; D010758:Phosphorus; D000255:Adenosine Triphosphate