| Forelimb postischaemic reactive hyperaemia is impaired by hypotensive low body negative pressure in healthy subjects. | |
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MedLine Citation:
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PMID: 16494605 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Local metabolic conditions adapt blood supply to metabolic requirement by a direct effect on vascular smooth muscles and indirectly by modulating sympathetic vasoconstrictor effectiveness. During exercise, sympathetic nervous activity could in turn interfere on local metabolic control of vascular tone and restrain blood flow to active muscles. In order to investigate that interaction non-invasively, we measured postischaemic reactive hyperaemia (RH) in the forelimb of eight healthy young men (22.7 +/- 2.1 years) at rest and during two levels of sympathetic stimulation using low body negative pressure (LBNP -15 and -30 mmHg). During every stages, RH was measured after 40, 60, 90 and 180 s of arterial occlusion, respectively. In control conditions, RH rose with duration of ischaemia (18.9, 24.2, 30.4, 33.1 ml min(-1) per 100 ml(-1) for 40, 60, 90 and 180 s of ischaemia, respectively). During non-hypotensive LBNP (-15 mmHg) sympathetic activation was associated with decreased forelimb blood flow (6.4 +/- 0.9 versus 3.9 +/- 0.6 ml min(-1) per 100 ml(-1), P<0.01), but RH were not significantly different from control conditions. During hypotensive tachycardia LBNP (-30 mmHg), RH were significantly lower than under the previous LBNP stage. This fall in RH was greater after the shortest gap of ischaemia and tapered off as arterial occlusion gap increased (-22.3, -13.1, -10.5 and -8.7% for 40, 60, 90 and 180 s of ischaemia, respectively). These results suggested that vascular tone adaptation to local metabolic conditions was modified by sympathetic nervous activation. This was particularly marked when an hypotensive-mediated sympathetic stimulation was opposed to short gaps of ischaemia. |
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Authors:
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Marc Charles; Vincent Pichot; Jean-Claude Barthelemy; Frederic Roche; Frederic Costes |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Clinical physiology and functional imaging Volume: 26 ISSN: 1475-0961 ISO Abbreviation: Clin Physiol Funct Imaging Publication Date: 2006 Mar |
Date Detail:
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Created Date: 2006-02-23 Completed Date: 2006-07-11 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101137604 Medline TA: Clin Physiol Funct Imaging Country: England |
Other Details:
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Languages: eng Pagination: 132-7 Citation Subset: IM |
Affiliation:
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Research Unity Physiology Physiopathology of Exercise and Handicap and CHU Saint-Etienne, North Hospital, EFCR Unity, University Jean Monnet, Saint-Etienne, France. marc.charles@univ-st-etienne.fr |
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Exercise / physiology* Forearm / blood supply* Humans Hyperemia / physiopathology* Ischemia / physiopathology Lower Body Negative Pressure* Male Regional Blood Flow Supine Position Sympathetic Nervous System / physiology Tachycardia / physiopathology Vascular Resistance / physiology* |
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