Arterial baroreflex control of sympathetic nerve activity during acute hypotension: effect of fitness
1 Department of Integrative Physiology and Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, Texas 76107; and 2 Copenhagen Muscle Research Center, Department of Anesthesia, Rigshospitalet, University of Copenhagen, DK-2200 Copenhagen, Denmark We examin...
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Veröffentlicht in: | American journal of physiology. Heart and circulatory physiology 2001-06, Vol.280 (6), p.H2524-H2532 |
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Sprache: | eng |
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Zusammenfassung: | 1 Department of Integrative Physiology and Cardiovascular
Research Institute, University of North Texas Health Science
Center, Fort Worth, Texas 76107; and 2 Copenhagen Muscle
Research Center, Department of Anesthesia, Rigshospitalet,
University of Copenhagen, DK-2200 Copenhagen, Denmark
We examined arterial baroreflex
control of muscle sympathetic nerve activity (MSNA) during abrupt
decreases in mean arterial pressure (MAP) and evaluated whether
endurance training alters baroreflex function. Acute hypotension was
induced nonpharmacologically in 14 healthy subjects, of which 7 were of
high fitness (HF) and 7 were of average fitness (AF), by releasing a
unilateral arterial thigh cuff after 9 min of resting ischemia
under two conditions: control, which used aortic and carotid baroreflex
(ABR and CBR, respectively) deactivation; and suction, which used ABR
deactivation alone. The application of neck suction to counteract
changes in carotid sinus transmural pressure during cuff release
significantly attenuated the MSNA response (which increased 134 ± 32 U/14 s) compared with control (which increased 195 ± 43 U/14
s) and caused a greater decrease in MAP (19 ± 2 vs. 15 ± 2 mmHg; P |
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ISSN: | 0363-6135 1522-1539 |
DOI: | 10.1152/ajpheart.2001.280.6.h2524 |