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Effect of muscle creatine content manipulation on contractile properties in mouse muscles
Author(s) -
Eijnde Bert O.,
Lebacq Jean,
Ramaekers Monique,
Hespel Peter
Publication year - 2004
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.10568
Subject(s) - creatine , medicine , endocrinology , soleus muscle , chemistry , beta (programming language) , phosphocreatine , glycolysis , stimulation , contraction (grammar) , skeletal muscle , metabolism , energy metabolism , computer science , programming language
Abstract The effects of muscle creatine manipulation on contractile properties in oxidative and glycolytic muscles were evaluated. Whereas control mice (NMRi; n = 12) received normal chow (5 g daily), three experimental groups were created by adding creatine monohydrate (CR group; 5%, 1 week; n = 13); β‐guanidinoproprionic acid, an inhibitor of cellular creatine uptake (β‐GPA group; 1%, 2 weeks; n = 12); or CR following β‐GPA (β‐GPA+CR group; n = 11). Total creatine (TCr) and the contractile properties of incubated soleus and extensor digitorum longus (EDL) muscles were determined. For the soleus, compared with control, TCr increased in the CR group (+25%), decreased in β‐GPA group (−50%), and remained stable in the β‐GPA+CR group, whereas, for the EDL, TCr was similar in the CR, and lower in the β‐GPA (−40%) and β‐GPA+CR (−15%) groups. None of the experimental groups (CR, β‐GPA, or β‐GPA+CR) showed changes in peak tension (P peak ), time to peak tension, or relaxation in soleus or EDL during twitch or tetanic stimulation. For the soleus, fatigue reduced P peak to ∼60% of initial P peak ; 5 min of recovery restored P peak to values ∼15% higher in CR than in controls. P peak recovery was not affected by β‐GPA or β‐GPA+CR in the soleus or any treatment in the EDL. Thus, peak tension recovery is enhanced by creatine intake in oxidative but not glycolytic muscles. This may be implicated in the beneficial action of creatine loading. Muscle Nerve 29: 428–435, 2004