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This Article Full Text Full Text (PDF) All Versions of this Article: 93/3/426    most recent expphysiol.2007.040477v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Matsunaga, S. Articles by Wada, M. Search for Related Content PubMed PubMed Citation Articles by Matsunaga, S. Articles by Wada, M.

¹ Research Center for Urban Health and Sports, Osaka City University, 3–3-138 Sugimoto, Sumiyoshi, Osaka 558–8585, Japan ² Pre School Education Department, Hachinohe Junior College, 13–384 Mihono, Hachinohe, Aomori 031–0844, Japan ³ Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden ⁴ Research Center of Health, Physical Fitness and Sports, Nagoya University, Furo, Chikusa, Nagoya, Aichi 464–8601, Japan ⁵ Graduate School of Integrated Arts and Sciences, Hiroshima University, 1–7-1 Kagamiyama, Higashi-hiroshima, Hiroshima 739–8521, Japan

The hypothesis tested in this study was that the extent to which sarcoplasmic reticulum (SR) Ca²⁺-ATPase is oxidized would correlate with a decline in its activity. For this purpose, changes in the SR Ca²⁺-sequestering ability and the contents of carbonyl and sulfhydryl groups during recovery after exercise were examined in the superficial portions of vastus lateralis muscles from rats subjected to 5 min running at an intensity corresponding to maximal oxygen uptake (50 m min^–1, 10% gradient). A single bout of exercise elicited a 22.4% reduction (P < 0.05) in SR Ca²⁺-ATPase activity. The decreased activity progressively reverted to normal levels during recovery after exercise, reaching normal levels after 60 min of recovery. This change was paralleled by a depressed SR Ca²⁺-uptake rate, and the proportional alteration in these two variables resulted in no change in the ratio of Ca²⁺-uptake rate to Ca²⁺-ATPase activity. The contents of SR Ca²⁺-ATPase protein and sulfhydryl groups in microsomes were unchanged after exercise and during recovery periods. In contrast, the content of carbonyl groups in SR Ca²⁺-ATPase behaved in an opposite manner to that of SR Ca²⁺-ATPase activity. An approximately 80% augmentation (P < 0.05) in the carbonyl group content occurred immediately after exercise. The elevated carbonyl content decreased towards normal levels during 60 min of recovery. These results are strongly suggestive that oxidation of SR Ca²⁺-ATPase is responsible, at least in part, for a decay in the SR Ca²⁺-pumping function produced by high-intensity exercise and imply that oxidized proteins may be repaired during recovery from exercise.

(Received 29 August 2007; accepted after revision 18 December 2007; first published online 21 December 2007)
Corresponding author S. Matsunaga: Research Center for Urban Health and Sports, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan. Email: matunaga{at}sports.osaka-cu.ac.jp