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This Article Full Text Full Text (PDF) All Versions of this Article: 106/4/1065    most recent 91611.2008v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map 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 Google Scholar Google Scholar Articles by Van Duijnhoven, N. T. L. Articles by Thijssen, D. H. J. Search for Related Content PubMed PubMed Citation Articles by Van Duijnhoven, N. T. L. Articles by Thijssen, D. H. J.

Effect of functional electrostimulation on impaired skin vasodilator responses to local heating in spinal cord injury

¹Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom; ²Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; ³Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands; ⁴Duyvensz-Nagel Research Laboratory, Rehabilitation Center, Amsterdam, The Netherlands; ⁵School of Sport Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia, Australia; and ⁶Department of Human Physiology, University of Oregon, Eugene, Oregon

Submitted 18 December 2008 ; accepted in final form 18 February 2009

Spinal cord injury (SCI) induces vascular adaptations below the level of the lesion, such as impaired cutaneous vasodilation. However, the mechanisms underlying these differences are unclear. The aim of this study is to examine arm and leg cutaneous vascular conductance (CVC) responses to local heating in 17 able-bodied controls (39 ± 13 yr) and 18 SCI subjects (42 ± 8 yr). SCI subjects were counterbalanced for functional electrostimulation (FES) cycling exercise (SCI-EX, n = 9) or control (SCI-C, n = 9) and reanalyzed after 8 wk. Arm and leg skin blood flow were measured by laser-Doppler flowmetry during local heating (42°C), resulting in an axon-reflex mediated first peak, nadir, and a primarily nitric oxide-dependent plateau phase. Data were expressed as a percentage of maximal CVC (44°C). CVC responses to local heating in the paralyzed leg, but also in the forearm of SCI subjects, were lower than in able-bodied controls (P < 0.05 and 0.01, respectively). The 8-wk intervention did not change forearm and leg CVC responses to local heating in SCI-C and SCI-EX, but increased femoral artery diameter in SCI-EX (P < 0.05). Interestingly, findings in skin microvessels contrast with conduit arteries, where physical (in)activity contributes to adaptations in SCI. The lower CVC responses in the paralyzed legs might suggest a role for inactivity in SCI, but the presence of impaired CVC responses in the normally active forearm suggests other mechanisms. This is supported by a lack of adaptation in skin microcirculation after FES cycle training. This might relate to the less frequent and smaller magnitude of skin blood flow responses to heat stimuli, compared with controls, than physical inactivity per se.

microcirculation; nitric oxide; inactivity; functional electrical stimulation