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Dissociation between force and maximal Na+, K+-ATPase activity in rat fast-twitch skeletal muscle with fatiguing in vitro stimulation

Goodman, Craig and Hayes, Alan and McKenna, Michael J (2009) Dissociation between force and maximal Na+, K+-ATPase activity in rat fast-twitch skeletal muscle with fatiguing in vitro stimulation. European Journal of Applied Physiology, 105 (4). pp. 575-583. ISSN 1439-6319

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Abstract

This study investigated whether high frequency in vitro stimulation of rat fast-twitch extensor digitorum longus muscle depresses Na+, K+-ATPase (NKA) activity as measured by the maximal in vitro 3-O-MFPase assay. EDL muscles subjected to 10 s continuous 100 Hz stimulation reduced tetanic force by 51.8 +/- 5.1% which recovered to 81.2 +/- 6.1% after 1 min and remained stable over 1 h recovery period. A second bout reduced force by 50.3 +/- 3.8% of initial but had no eVect on 3-O-MFPase activity. Three minutes of intermittent stimulation (1 s at 100 Hz and 4 s recovery) resulted in 87.0 +/- 2.8% decline force with slow recovery (62.7 +/- 5.8% of initial after 1 h). The second 3-min bout reduced force by 83.3 +/- 3.6% of initial with no change in maximal 3-O-MFPase activity. These Wndings contrast previous human studies where fatiguing voluntary exercise depresses maximal NKA activity. This suggests that NKA in rat fast-twitch muscle is resistant to fatigue-induced inactivation under these conditions tions. Furthermore, the loss of force with fatigue was not related to depressed maximal NKA activity.

Item Type: Article
Uncontrolled Keywords: ResPubID18247. 3-O-MFPase activity, EDL, muscle in vitro stimulation, ion regulation, Na+, K+-pump, skeletal muscle, muscle contractility, contractile, NKA
Subjects: FOR Classification > 0606 Physiology
FOR Classification > 1116 Medical Physiology
SEO Classification > 970106 Expanding Knowledge in the Biological Sciences
Faculty/School/Research Centre/Department > Centre for Ageing, Rehabilitation, Exercise & Sport Science (CARES)
Depositing User: VUIR
Date Deposited: 17 Oct 2011 01:40
Last Modified: 23 Dec 2014 22:27
URI: http://vuir.vu.edu.au/id/eprint/4302
DOI: 10.1007/s00421-008-0937-x
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Citations in Scopus: 3 - View on Scopus

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