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Effects of ageing and exercise training on eNOS uncoupling in skeletal muscle resistance arterioles
| Content Provider | Scilit |
|---|---|
| Author | Sindler, Amy L. Delp, Michael D. Reyes, Rafael Wu, Guoyao Muller-Delp, Judy M. |
| Copyright Year | 2009 |
| Description | Journal: The Journal of physiology Reduced availability of tetrahydrobiopterin (BH(4)) contributes to the age-related decline of nitric oxide (NO)-mediated vasodilatation of soleus muscle arterioles. Depending on availability of substrate and/or necessary co-factors, endothelial nitric oxide synthase (eNOS) can generate NO and/or superoxide (O(2)(-)). We evaluated the effects of age and chronic exercise on flow-induced vasodilatation and levels of NO and O(2)(-) in soleus muscle arterioles. Young (3 months) and old (22 months) male rats were exercise trained or remained sedentary (SED) for 10 weeks. Flow-stimulated NO and O(2)(-), as well as BH(4) and l-arginine content, were determined in soleus muscle arterioles. Flow-induced vasodilatation was assessed under control conditions and during the blockade of O(2)(-) and/or hydrogen peroxide. Exercise training enhanced flow-induced vasodilatation in arterioles from young and old rats. Old age reduced, and exercise training restored, BH(4) content and flow-stimulated NO availability. Flow-stimulated, eNOS-derived O(2)(-) levels were higher in arterioles from old SED compared to those from young SED rats. Exercise training increased flow-stimulated eNOS-derived O(2)(-) levels in arterioles from young but not old rats. O(2)(-) scavenging with Tempol reduced flow-induced vasodilatation from all groups except young SED rats. Addition of catalase to Tempol-treated arterioles eliminated flow-induced vasodilatation in arterioles from all groups. Catalase reduced flow-induced vasodilatation from all groups. In Tempol-treated arterioles, flow-induced vasodilatation was restored by deferoxamine, an iron chelator. These data indicate that uncoupling of eNOS contributes to the age-related decline in flow-induced vasodilatation; however, reactive oxygen species are required for flow-induced vasodilatation in soleus muscle arterioles from young and old rats. |
| Related Links | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2746616/pdf |
| Ending Page | 3897 |
| Page Count | 13 |
| Starting Page | 3885 |
| ISSN | 00223751 |
| e-ISSN | 14697793 |
| DOI | 10.1113/jphysiol.2009.172221 |
| Journal | The Journal of physiology |
| Issue Number | 15 |
| Volume Number | 587 |
| Language | English |
| Publisher | Wiley-Blackwell |
| Publisher Date | 2009-07-30 |
| Access Restriction | Open |
| Subject Keyword | Journal: The Journal of physiology Skeletal Muscle Exercise Training Induced Vasodilatation Soleus Muscle |
| Content Type | Text |
| Subject | Physiology Sports Science |
