Metabolic fluctuation during a muscle contraction cycle.
Gated 31P-nuclear magnetic resonance followed the metabolic fluctuation in rat gastrocnemius muscle during a contraction cycle. Within 16 ms after stimulation, the phosphocreatine (PCr) level drops 11.3% from its reference state. The PCr minimum corresponds closely to the time of maximum force contraction. Pi increases stoichiometrically, while ATP remains constant. During a twitch, PCr hydrolysis produces 3.1 mumol ATP/g tissue, which is substantially higher than the reported 0.3 mumol ATP.twitch-1.g tissue-1 derived from steady-state experiments. The results reveal that a substantial energy fluctuation accompanies a muscle twitch.
Chung
Y
Y
Department of Biological Chemistry, University of California, Davis 95616-8635, USA.
Sharman
R
R
Carlsen
R
R
Unger
S W
SW
Larson
D
D
Jue
T
T
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D005260:Female; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D009119:Muscle Contraction; D009132:Muscles / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D010725:Phosphocreatine; D000255:Adenosine Triphosphate