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Baroreflex modulation of muscle sympathetic nerve activity at rest does not differ between morning and afternoon
The incidence of cardiovascular events is significantly higher in the morning than other times of day. This has previously been associated with poor blood pressure control via the cardiac baroreflex. However, it is not known whether diurnal variation exists in vascular sympathetic baroreflex functio...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4557114/ https://www.ncbi.nlm.nih.gov/pubmed/26388723 http://dx.doi.org/10.3389/fnins.2015.00312 |
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author | Hissen, Sarah L. Macefield, Vaughan G. Brown, Rachael Witter, Trevor Taylor, Chloe E. |
author_facet | Hissen, Sarah L. Macefield, Vaughan G. Brown, Rachael Witter, Trevor Taylor, Chloe E. |
author_sort | Hissen, Sarah L. |
collection | PubMed |
description | The incidence of cardiovascular events is significantly higher in the morning than other times of day. This has previously been associated with poor blood pressure control via the cardiac baroreflex. However, it is not known whether diurnal variation exists in vascular sympathetic baroreflex function, in which blood pressure is regulated via muscle sympathetic nerve activity (MSNA). The aim of this study was to compare vascular sympathetic baroreflex sensitivity (BRS) in the same participants between the morning and afternoon. In 10 participants (mean age 22 ± 2.9 years), continuous measurements of blood pressure, heart rate and MSNA were made during 10 min of rest in the morning (between 0900 and 1000 h) and afternoon (between 1400 and 1500 h). Spontaneous vascular sympathetic BRS was quantified by plotting MSNA burst incidence against diastolic pressure (vascular sympathetic BRS(inc)), and by plotting total MSNA against diastolic pressure (vascular sympathetic BRS(total)). Significant vascular sympathetic BRS(inc) and vascular sympathetic BRS(total) slopes were obtained for 10 participants at both times of day. There was no significant difference in vascular sympathetic BRS(inc) between morning (−2.2 ± 0.6% bursts/mmHg) and afternoon (−2.5 ± 0.2% bursts/mmHg; P = 0.68) sessions. Similarly, vascular sympathetic BRS(total) did not differ significantly between the morning (−3.0±0.5 AU/beat/mmHg) and afternoon (−2.9 ± 0.4 AU/beat/mmHg; P = 0.89). It is concluded that in healthy, young individuals baroreflex modulation of MSNA at rest does not differ between the morning and afternoon. The results indicate that recording MSNA at different times of the day is a valid means of assessing sympathetic function. |
format | Online Article Text |
id | pubmed-4557114 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-45571142015-09-18 Baroreflex modulation of muscle sympathetic nerve activity at rest does not differ between morning and afternoon Hissen, Sarah L. Macefield, Vaughan G. Brown, Rachael Witter, Trevor Taylor, Chloe E. Front Neurosci Neurology The incidence of cardiovascular events is significantly higher in the morning than other times of day. This has previously been associated with poor blood pressure control via the cardiac baroreflex. However, it is not known whether diurnal variation exists in vascular sympathetic baroreflex function, in which blood pressure is regulated via muscle sympathetic nerve activity (MSNA). The aim of this study was to compare vascular sympathetic baroreflex sensitivity (BRS) in the same participants between the morning and afternoon. In 10 participants (mean age 22 ± 2.9 years), continuous measurements of blood pressure, heart rate and MSNA were made during 10 min of rest in the morning (between 0900 and 1000 h) and afternoon (between 1400 and 1500 h). Spontaneous vascular sympathetic BRS was quantified by plotting MSNA burst incidence against diastolic pressure (vascular sympathetic BRS(inc)), and by plotting total MSNA against diastolic pressure (vascular sympathetic BRS(total)). Significant vascular sympathetic BRS(inc) and vascular sympathetic BRS(total) slopes were obtained for 10 participants at both times of day. There was no significant difference in vascular sympathetic BRS(inc) between morning (−2.2 ± 0.6% bursts/mmHg) and afternoon (−2.5 ± 0.2% bursts/mmHg; P = 0.68) sessions. Similarly, vascular sympathetic BRS(total) did not differ significantly between the morning (−3.0±0.5 AU/beat/mmHg) and afternoon (−2.9 ± 0.4 AU/beat/mmHg; P = 0.89). It is concluded that in healthy, young individuals baroreflex modulation of MSNA at rest does not differ between the morning and afternoon. The results indicate that recording MSNA at different times of the day is a valid means of assessing sympathetic function. Frontiers Media S.A. 2015-09-02 /pmc/articles/PMC4557114/ /pubmed/26388723 http://dx.doi.org/10.3389/fnins.2015.00312 Text en Copyright © 2015 Hissen, Macefield, Brown, Witter and Taylor. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Neurology Hissen, Sarah L. Macefield, Vaughan G. Brown, Rachael Witter, Trevor Taylor, Chloe E. Baroreflex modulation of muscle sympathetic nerve activity at rest does not differ between morning and afternoon |
title | Baroreflex modulation of muscle sympathetic nerve activity at rest does not differ between morning and afternoon |
title_full | Baroreflex modulation of muscle sympathetic nerve activity at rest does not differ between morning and afternoon |
title_fullStr | Baroreflex modulation of muscle sympathetic nerve activity at rest does not differ between morning and afternoon |
title_full_unstemmed | Baroreflex modulation of muscle sympathetic nerve activity at rest does not differ between morning and afternoon |
title_short | Baroreflex modulation of muscle sympathetic nerve activity at rest does not differ between morning and afternoon |
title_sort | baroreflex modulation of muscle sympathetic nerve activity at rest does not differ between morning and afternoon |
topic | Neurology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4557114/ https://www.ncbi.nlm.nih.gov/pubmed/26388723 http://dx.doi.org/10.3389/fnins.2015.00312 |
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