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Sex comparisons in muscle sympathetic nerve activity and arterial pressure oscillations during progressive central hypovolemia

Increased tolerance to central hypovolemia is generally associated with greater sympathoexcitation, high-frequency oscillatory patterns of mean arterial pressure (MAP), and tachycardia. On average, women are less tolerant to central hypovolemia than men; however, the autonomic mechanisms governing t...

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Autores principales: Carter III, Robert, Hinojosa-Laborde, Carmen, Convertino, Victor A
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley & Sons, Ltd 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510624/
https://www.ncbi.nlm.nih.gov/pubmed/26109186
http://dx.doi.org/10.14814/phy2.12420
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author Carter III, Robert
Hinojosa-Laborde, Carmen
Convertino, Victor A
author_facet Carter III, Robert
Hinojosa-Laborde, Carmen
Convertino, Victor A
author_sort Carter III, Robert
collection PubMed
description Increased tolerance to central hypovolemia is generally associated with greater sympathoexcitation, high-frequency oscillatory patterns of mean arterial pressure (MAP), and tachycardia. On average, women are less tolerant to central hypovolemia than men; however, the autonomic mechanisms governing these comparisons are not fully understood. We tested the hypothesis that women with relatively high tolerance (HT) to central hypovolemia would display similar physiological reserve capacity for sympathoexcitation and oscillations in MAP at presyncope compared to HT men. About 10 men and five women were exposed to progressive lower body negative pressure (LBNP) until the presence of presyncopal symptoms. Based on our previous classification system, all subjects were classified as HT because they completed at least −60 mmHg LBNP. Muscle sympathetic serve activity (MSNA) was measured directly from the peroneal nerve via microneurography and arterial pressure (AP) was measured at the finger by photoplethysmography. LBNP time to presyncope was less (P < 0.01) in women (1727 ± 70 sec) than in men (2022 ± 201 sec). At presyncope, average MSNA in men (50 ± 12 bursts/min) and women (51 ± 7 bursts/min) was similar (P = 0.87). Coincident with similar stroke volume (SV) at presyncope, women had similar MAP and heart rates. However, women had less physiological reserve capacity for SV, AP-MSNA coherence, and oscillations in the high-frequency (HF) components of arterial pressure compared to men. Contrary to our hypothesis, lower tolerance to central hypovolemia in women was not associated with sympathoexcitation, but can be explained, in part by lower physiological reserve to elicit oscillatory patterns in AP, maintenance of AP-MSNA coherence and SV when compared to men.
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spelling pubmed-45106242015-07-28 Sex comparisons in muscle sympathetic nerve activity and arterial pressure oscillations during progressive central hypovolemia Carter III, Robert Hinojosa-Laborde, Carmen Convertino, Victor A Physiol Rep Original Research Increased tolerance to central hypovolemia is generally associated with greater sympathoexcitation, high-frequency oscillatory patterns of mean arterial pressure (MAP), and tachycardia. On average, women are less tolerant to central hypovolemia than men; however, the autonomic mechanisms governing these comparisons are not fully understood. We tested the hypothesis that women with relatively high tolerance (HT) to central hypovolemia would display similar physiological reserve capacity for sympathoexcitation and oscillations in MAP at presyncope compared to HT men. About 10 men and five women were exposed to progressive lower body negative pressure (LBNP) until the presence of presyncopal symptoms. Based on our previous classification system, all subjects were classified as HT because they completed at least −60 mmHg LBNP. Muscle sympathetic serve activity (MSNA) was measured directly from the peroneal nerve via microneurography and arterial pressure (AP) was measured at the finger by photoplethysmography. LBNP time to presyncope was less (P < 0.01) in women (1727 ± 70 sec) than in men (2022 ± 201 sec). At presyncope, average MSNA in men (50 ± 12 bursts/min) and women (51 ± 7 bursts/min) was similar (P = 0.87). Coincident with similar stroke volume (SV) at presyncope, women had similar MAP and heart rates. However, women had less physiological reserve capacity for SV, AP-MSNA coherence, and oscillations in the high-frequency (HF) components of arterial pressure compared to men. Contrary to our hypothesis, lower tolerance to central hypovolemia in women was not associated with sympathoexcitation, but can be explained, in part by lower physiological reserve to elicit oscillatory patterns in AP, maintenance of AP-MSNA coherence and SV when compared to men. John Wiley & Sons, Ltd 2015-06-24 /pmc/articles/PMC4510624/ /pubmed/26109186 http://dx.doi.org/10.14814/phy2.12420 Text en Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society. http://creativecommons.org/licenses/by/4.0/ This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Research
Carter III, Robert
Hinojosa-Laborde, Carmen
Convertino, Victor A
Sex comparisons in muscle sympathetic nerve activity and arterial pressure oscillations during progressive central hypovolemia
title Sex comparisons in muscle sympathetic nerve activity and arterial pressure oscillations during progressive central hypovolemia
title_full Sex comparisons in muscle sympathetic nerve activity and arterial pressure oscillations during progressive central hypovolemia
title_fullStr Sex comparisons in muscle sympathetic nerve activity and arterial pressure oscillations during progressive central hypovolemia
title_full_unstemmed Sex comparisons in muscle sympathetic nerve activity and arterial pressure oscillations during progressive central hypovolemia
title_short Sex comparisons in muscle sympathetic nerve activity and arterial pressure oscillations during progressive central hypovolemia
title_sort sex comparisons in muscle sympathetic nerve activity and arterial pressure oscillations during progressive central hypovolemia
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510624/
https://www.ncbi.nlm.nih.gov/pubmed/26109186
http://dx.doi.org/10.14814/phy2.12420
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