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This Article Full Text Full Text (PDF) All Versions of this Article: 585/1/253    most recent jphysiol.2007.141309v1 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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Wadley, G. D. Articles by McConell, G. K. Search for Related Content PubMed PubMed Citation Articles by Wadley, G. D. Articles by McConell, G. K. Related Collections Skeletal Muscle and Exercise

¹ Department of Physiology, University of Melbourne, Parkville, Victoria, 3010, Australia
² Department of Physiology, Monash University, Clayton, Victoria, 3800, Australia

Nitric oxide is a potential regulator of mitochondrial biogenesis. Therefore, we investigated if mice deficient in endothelial nitric oxide synthase (eNOS^–/–) or neuronal NOS (nNOS^–/–) have attenuated activation of skeletal muscle mitochondrial biogenesis in response to exercise. eNOS^–/–, nNOS^–/– and C57Bl/6 (CON) mice (16.3 ± 0.2 weeks old) either remained in their cages (basal) or ran on a treadmill (16 m min^–1, 5% grade) for 60 min (n = 8 per group) and were killed 6 h after exercise. Other eNOS^–/–, nNOS^–/– and CON mice exercise trained for 9 days (60 min per day) and were killed 24 h after the last bout of exercise training. eNOS^–/– mice had significantly higher nNOS protein and nNOS^–/– mice had significantly higher eNOS protein in the EDL, but not the soleus. The basal mitochondrial biogenesis markers NRF1, NRF2 and mtTFA mRNA were significantly (P< 0.05) higher in the soleus and EDL of nNOS^–/– mice whilst basal citrate synthase activity was higher in the soleus and basal PGC-1 mRNA higher in the EDL. Also, eNOS^–/– mice had significantly higher basal citrate synthase activity in the soleus but not the EDL. Acute exercise increased (P< 0.05) PGC-1 mRNA in soleus and EDL and NRF2 mRNA in the EDL to a similar extent in all genotypes. In addition, short-term exercise training significantly increased cytochrome c protein in all genotypes (P< 0.05) in the EDL. In conclusion, eNOS and nNOS are differentially involved in the basal regulation of mitochondrial biogenesis in skeletal muscle but are not critical for exercise-induced increases in mitochondrial biogenesis in skeletal muscle.

(Received 25 July 2007; accepted after revision 25 September 2007; first published online 4 October 2007)
Corresponding author G. Wadley: Department of Physiology, University of Melbourne, Parkville, 3010, Australia. Email: gdwadley{at}unimelb.edu.au

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