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This Article Full Text Full Text (PDF) All Versions of this Article: 586/4/1137    most recent jphysiol.2007.145722v1 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 Google Scholar Articles by Kooijman, M. Articles by Hopman, M. T. E. PubMed PubMed Citation Articles by Kooijman, M. Articles by Hopman, M. T. E. Related Collections Cardiovascular

¹ Department of Physiology
⁵ Department of Pharmacology-Toxicology
⁴ Department of Nephrology, Radboud University Nijmegen Medical Centre, the Netherlands
² Rehabilitation Centre St Maartenskliniek, Nijmegen, the Netherlands
³ Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK
⁶ School of Sports Science, Exercise and Health, The University of Western Australia, Perth, Australia

Flow-mediated dilatation (FMD) of the brachial and radial arteries is an important research tool for assessment of endothelial function in vivo, and is nitric oxide (NO) dependent. The leg skeletal muscle vascular bed is an important territory for studies in exercise physiology. However, the role of endothelial NO in the FMD response of lower limb arteries has never been investigated. The purpose of this study was to examine the contribution of NO to FMD in the superficial femoral artery in healthy subjects. Since physical inactivity may affect endothelial function, and therefore NO availability, spinal cord-injured (SCI) individuals were included as a model of extreme deconditioning. In eight healthy men (34 ± 13 years) and six SCI individuals (37 ± 10 years), the 5 min FMD response in the superficial femoral artery was assessed by echo-Doppler, both during infusion of saline and during infusion of the NO synthase blocker N^G-monomethyl-L-arginine (L-NMMA). In a subset of the controls (n = 6), the 10 min FMD response was also examined using the same procedure. The 5 min FMD response in controls (4.2 ± 0.3%) was significantly diminished during L-NMMA infusion (1.0 ± 0.2%, P < 0.001). In SCI, L-NMMA also significantly decreased the FMD response (from 8.2 ± 0.4% during saline to 2.4 ± 0.5% during L-NMMA infusion). The hyperaemic flow response during the first 45 s after cuff deflation was lower in both groups during infusion of L-NMMA, but the effect of L-NMMA on FMD persisted in both groups after correction for the shear stress stimulus. The 10 min FMD was not affected by L-NMMA (saline: 5.4 ± 1.6%, L-NMMA: 5.6 ± 1.5%). Superficial femoral artery FMD in response to distal arterial occlusion for a period of 5 min is predominantly mediated by NO in healthy men and in the extremely deconditioned legs of SCI individuals.

(Received 28 September 2007; accepted after revision 13 December 2007; first published online 20 December 2007)
Corresponding author M.T.E. Hopman: Radboud University Nijmegen Medical Centre, Department of Physiology, Geert Grooteplein Noord 21, 6525 EZ Nijmegen, The Netherlands. Email: m.hopman{at}fysiol.umcn.nl

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				D. H. J. Thijssen, M. Kooijman, P. C. E. de Groot, M. W. P. Bleeker, P. Smits, D. J. Green, and M. T. E. Hopman Endothelium-dependent and -independent vasodilation of the superficial femoral artery in spinal cord-injured subjects J Appl Physiol, May 1, 2008; 104(5): 1387 - 1393. [Abstract] [Full Text] [PDF]