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Baroreflex modulation of muscle sympathetic nerve activity during cold pressor test in humansThe purpose of this project was to test the hypothesis that baroreceptor modulation of muscle sympathetic nerve activity (MSNA) and heart rate is altered during the cold pressor test. Ten subjects were exposed to a cold pressor test by immersing a hand in ice water for 3 min while arterial blood pressure, heart rate, and MSNA were recorded. During the second and third minute of the cold pressor test, blood pressure was lowered and then raised by intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure was more negative (P < 0.005) during the cold pressor test (-244.9 +/- 26.3 units x beat(-1) x mmHg(-1)) when compared with control conditions (-138.8 +/- 18.6 units x beat(-1) x mmHg(-1)), whereas no significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. These data suggest that baroreceptors remain capable of modulating MSNA and heart rate during a cold pressor test; however, the sensitivity of baroreflex modulation of MSNA is elevated without altering the sensitivity of baroreflex control of heart rate.
Document ID
20040088380
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Cui, Jian
(Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas Texas 75231, United States)
Wilson, Thad E.
Crandall, Craig G.
Date Acquired
August 21, 2013
Publication Date
May 1, 2002
Publication Information
Publication: American journal of physiology. Heart and circulatory physiology
Volume: 282
Issue: 5
ISSN: 0363-6135
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: HL-10488
CONTRACT_GRANT: HL-61388
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Cardiopulmonary
Non-NASA Center

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