Antioxidant treatment with N-acetylcysteine regulates mammalian skeletal muscle Na+-K+-ATPase ∝ gene expression during repeated contractions

Murphy, K.T., Medved, I., Brown, M., Cameron-Smith, D. and McKenna, M. 2008, Antioxidant treatment with N-acetylcysteine regulates mammalian skeletal muscle Na+-K+-ATPase ∝ gene expression during repeated contractions, Experimental physiology, vol. 93, no. 12, pp. 1239-1248.


Title Antioxidant treatment with N-acetylcysteine regulates mammalian skeletal muscle Na+-K+-ATPase ∝ gene expression during repeated contractions
Author(s) Murphy, K.T.
Medved, I.
Brown, M.
Cameron-Smith, D.
McKenna, M.
Journal name Experimental physiology
Volume number 93
Issue number 12
Start page 1239
End page 1248
Publisher Cambridge University Press for the Physiological Society
Place of publication Cambridge, England
Publication date 2008-12-01
ISSN 0958-0670
1469-445X
Summary Exercise increases Na+–K+ pump isoform gene expression and elevates muscle reactive oxygen species (ROS). We investigated whether enhanced ROS scavenging induced with the antioxidant N-acetylcysteine (NAC) blunted the increase in Na+–K+ pump mRNA during repeated contractions in human and rat muscle. In experiment 1, well-trained subjects received saline or NAC intravenously prior to and during 45 min cycling. Vastus lateralis muscle biopsies were taken pre-infusion and following exercise. In experiment 2, isolated rat extensor digitorum longus muscles were pre-incubated without or with 10 mm NAC and then rested or stimulated electrically at 60 Hz for 90 s. After 3 h recovery, muscles were frozen. In both experiments, the muscles were analysed for Na+–K+ pump α1, α2, α3, β1, β2 and β3 mRNA. In experiment 1, exercise increased α2 mRNA by 1.0-fold (P = 0.03), but α2 mRNA was reduced by 0.40-fold with NAC (P = 0.03). Exercise increased α3, β1 and β2 mRNA by 2.0- to 3.4-fold (P < 0.05), but these were not affected by NAC (P > 0.32). Neither exercise nor NAC altered α1 or β3 mRNA (P > 0.31). In experiment 2, electrical stimulation increased α1, α2 and α3 mRNA by 2.3- to 17.4-fold (P < 0.05), but these changes were abolished by NAC (P > 0.07). Electrical stimulation almost completely reduced β1 mRNA but only in the presence of NAC (P < 0.01). Neither electrical stimulation nor NAC altered β2 or β3 mRNA (P > 0.09). In conclusion, NAC attenuated the increase in Na+–K+ pump α2 mRNA with exercise in human muscle and all α isoforms with electrical stimulation in rat muscle. This indicates a regulatory role for ROS in Na+–K+ pump α isoform mRNA in mammalian muscle during repeated contractions.
Language eng
Field of Research 111601 Cell Physiology
Socio Economic Objective 970111 Expanding Knowledge in the Medical and Health Sciences
HERDC Research category C1 Refereed article in a scholarly journal
ERA Research output type C Journal article
HERDC collection year 2008
Persistent URL http://hdl.handle.net/10536/DRO/DU:30017718

Document type: Journal Article
Collection: School of Exercise and Nutrition Sciences
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