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Updated: Jul 26, 2026

Procedures for Rat in situ Skeletal Muscle Contractile Properties
Published on: October 15, 2011
Metabolic fluctuation during a muscle contraction cycle
Y Chung1, R Sharman, R Carlsen
1Department of Biological Chemistry, University of California, Davis 95616-8635, USA.
Abstract:
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.
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