HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 103/4/1212    most recent 00437.2007v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Duhamel, T. A. Articles by Green, H. J. Search for Related Content PubMed PubMed Citation Articles by Duhamel, T. A. Articles by Green, H. J.

Muscle sarcoplasmic reticulum calcium regulation in humans during consecutive days of exercise and recovery

Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada

Submitted 20 April 2007 ; accepted in final form 4 July 2007

The study investigated the hypothesis that three consecutive days of prolonged cycle exercise would result in a sustained reduction in the Ca²⁺-cycling properties of the vastus lateralis in the absence of changes in the sarcoplasmic (endoplasmic) reticulum Ca²⁺-ATPase (SERCA) protein. Tissue samples were obtained at preexercise (Pre) and postexercise (Post) on day 1 (E1) and day 3 (E3) and during recovery day 1 (R1), day 2 (R2), and day 3 (R3) in 12 active but untrained volunteers (age 19.2 ± 0.27 yr; mean ± SE) and analyzed for changes (nmol·mg protein^–1·min^–1) in maximal Ca²⁺-ATPase activity (V_max), Ca²⁺ uptake and Ca²⁺ release (phase 1 and phase 2), and SERCA isoform expression (SERCA1a and SERCA2a). At E1, reductions (P < 0.05) from Pre to Post in V_max (150 ± 7 vs. 121 ± 7), Ca²⁺ uptake (7.79 ± 0.28 vs. 5.71 ± 0.33), and both phases of Ca²⁺ release (phase 1, 20.3 ± 1.3 vs. 15.2 ± 1.1; phase 2, 7.70 ± 0.60 vs. 4.99 ± 0.48) were found. In contrast to V_max, which recovered at Pre E3 and then remained stable at Post E3 and throughout recovery, Ca²⁺ uptake remained depressed (P < 0.05) at E3 Pre and Post and at R1 as did phase 2 of Ca²⁺ release. Exercise resulted in an increase (P < 0.05) in SERCA1a (14% at R2) but not SERCA2a. It is concluded that rapidly adapting mechanisms protect V_max following the onset of regular exercise but not Ca²⁺ uptake and Ca²⁺ release.

short-term training; calcium-adenosinetriphosphatase; calcium uptake; calcium release; SERCA isoforms

This article has been cited by other articles:

				H. J. Green, T. A. Duhamel, R. D. Stewart, A. R. Tupling, and J. Ouyang Dissociation between changes in muscle Na+-K+-ATPase isoform abundance and activity with consecutive days of exercise and recovery Am J Physiol Endocrinol Metab, April 1, 2008; 294(4): E761 - E767. [Abstract] [Full Text] [PDF]