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Time-of-day variation in vascular function

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journal contribution
posted on 2016-10-25, 12:44 authored by Glenn C. Rodrigo, M. Denniff
What is the topic of this review? This report looks at the role of endothelial nitric oxide signalling in the time-of-day variation in vasoconstriction of resistance vessels. What advances does it highlight? It highlights a time-of-day variation in contraction of mesenteric arteries, characterized by a reduced contractile response to either phenylephrine or high K(+) and increased relaxation in response to acetylcholine during the active period. This time-of-day variation in contraction results from a difference in endothelial nitric oxide synthase (eNOS) signalling that correlates with levels of eNOS expression, which peak during the active period and may have far reaching physiological consequences beyond regulation of blood pressure. There is a strong time-of-day variation in the vasoconstriction in response to sympathetic stimulation that may contribute to the time-of-day variation in blood pressure, which is characterized by a dip in blood pressure during the individual's rest period when sympathetic activity is low. Vasoconstriction is known to be regulated tightly by nitric oxide signalling from the endothelial cells, so we have looked at the effect of time-of-day on levels of endothelial nitric oxide synthase (eNOS) and vascular contractility. Mesenteric arteries isolated from the nocturnal rat exhibit a time-of-day variation in their contractile response to α1 -adrenoreceptor and muscarinic activation, which is characterized by a reduced vasoconstriction in response to phenylephrine and enhanced vasodilatation in response to acetylcholine during the rat's active period at night. An increase in eNOS signalling during the active period is responsible for this time-of-day difference in response to phenylephrine and acetylcholine and correlates with the large increase in eNOS expression (mRNA and protein) during the active period, possibly driven by the presence of a functioning peripheral circadian clock. This increase in eNOS signalling may function to limit the increase in peripheral resistance and therefore blood pressure during the increased sympathetic activity.

History

Citation

Experimental Physiology, 2016, 101 (8), pp. 1030-1034

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/School of Medicine/Department of Cardiovascular Sciences

Version

  • AM (Accepted Manuscript)

Published in

Experimental Physiology

Publisher

Wiley for Physiological Society

issn

0958-0670

eissn

1469-445X

Acceptance date

2016-06-06

Copyright date

2016

Available date

2017-07-30

Publisher version

http://onlinelibrary.wiley.com/doi/10.1113/EP085780/abstract;jsessionid=35941E56AB20D65A7B97DB8356EE0723.f02t02?systemMessage=Due+to+essential+maintenance+the+subscribe/renew+pages+will+be+unavailable+on+Wednesday+26+October+between+02:00+-+08:00+BST/+09:00+–+15:00++SGT/+21:00-+03:00+EDT.+Apologies+for+the+inconvenience.#footer-article-info

Notes

Following the embargo period the above license applies.

Language

en

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