Muscle Na+-K+-ATPase activity and isoform adaptations to intense interval exercise and training in well-trained athletes

Aughey, R, Murphy, K, Clark, S, Garnham, A, Snow, R, Cameron-Smith, D, Hawley, J and McKenna, M 2007, 'Muscle Na+-K+-ATPase activity and isoform adaptations to intense interval exercise and training in well-trained athletes', Journal of Applied Physiology, vol. 103, pp. 39-47.


Document type: Journal Article
Collection: Journal Articles

Title Muscle Na+-K+-ATPase activity and isoform adaptations to intense interval exercise and training in well-trained athletes
Author(s) Aughey, R
Murphy, K
Clark, S
Garnham, A
Snow, R
Cameron-Smith, D
Hawley, J
McKenna, M
Year 2007
Journal name Journal of Applied Physiology
Volume number 103
Start page 39
End page 47
Total pages 9
Publisher American Physiological Society
Abstract The Na+-K+-ATPase enzyme is vital in skeletal muscle function. We investigated the effects of acute high-intensity interval exercise, before and following high-intensity training (HIT), on muscle Na+-K+-ATPase maximal activity, content, and isoform mRNA expression and protein abundance. Twelve endurance-trained athletes were tested at baseline, pretrain, and after 3 wk of HIT (posttrain), which comprised seven sessions of X 5-min interval cycling at 80% peak power output. Vastus lateralis muscle was biopsied at rest (baseline) and both at rest and immediately postexercise during the first (pretrain) and seventh (posttrain) training sessions. Muscle was analyzed for Na+-K+-ATPase maximal activity (3-O-MFPase), content ([H-3]ouabain binding), isoform mRNA expression (RT-PCR), and protein abundance (Western blotting). All baseline-to-pretrain measures were stable. Pretrain, acute (exercise decreased 3-O-MFPase activity [12.7% (SD 5.1), P < 0.05], increased alpha(1) alpha(2) and alpha(3) mRNA expression (1.4-, 2.8-, and 3.4-fold, increased respectively. P < 0.05) with unchanged beta-isoform mRNA or protein,abundance of any isoform. In resting muscle, HIT increased (P < 0.05) 3-O-MFPase activity by 5.5% (SD 2.9), and alpha(3) and beta(3) mRNA expression by 3.0- and 0.5-fold, respectively, with unchanged Na+-K+-ATPase content or isoform protein abundance. Posttrain, the, cute exercise induced decline in 3-O-MFPase activity and increase in ( alpha(1) and alpha(3) mRNA each persisted (P < 0.05); the postexercise 3-O-MFPase activity was also higher after HIT (P < 0.05). Thus HIT,augmented Na+-K+-ATPase maximal activity despite unchanged total content and isoform protein abundance. Elevated Na+-K+-ATPase activity postexercise may contribute to reduced fatigue after training. The Na+-K+-ATPase mRNA response to interval exercise of increased alpha- but not beta-mRNA was largely preserved posttrain, suggesting a functional role of et mRNA upregulation.
Subject Exercise Physiology
Keyword(s) Human Skeletal-Muscle
Messenger-Rna Expression
In-Vitro
Prolonged Exercise
Cycling Exercise
Pump
Potassium
Fatigue
Increases
Contractility
DOI - identifier 10.1152/japplphysiol.00236.2006
Copyright notice © 2007 the American Physiological Society
ISSN 8750-7587
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