The influence of barosensory vessel mechanics on the vascular sympathetic baroreflex: Insights into ageing and blood pressure homeostasis

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Author
Lord, Rachel
Wakeham, Denis
Pugh, Christopher J. A.
Simpson, Lydia
Talbot, Jack
Lodge, Freya
Curry, Bryony
Dawkins, Tony
Shave, Rob
Moore, Jonathan
Date
2020-07-10Acceptance date
2020-07-02
Date Accepted
2020-07-03
Type
Article
acceptedVersion
Publisher
American Physiological Society
ISSN
0363-6135
1522-1539 (online)
Embargoed until
2021-07-10
Metadata
Show full item recordAbstract
Changes in the arterial baroreflex arc contribute to elevated sympathetic outflow and altered reflex control of blood pressure with human ageing. Utilizing ultrasound and sympathetic microneurography (muscle sympathetic nerve activity; MSNA) we investigated the relationships between aortic and carotid artery wall tension (indices of baroreceptor activation) and the vascular sympathetic baroreflex operating point (OP; MSNA burst incidence) in healthy, normotensive young (n = 27, 23 ± 3 years) and middle-aged men (n = 22, 55 ± 4 years). In young men, the OP was positively related to the magnitude and rate of unloading and time spent unloaded in the aortic artery (r = 0.56, 0.65 and 0.51, P = 0.02, 0.003 and 0.03), but not related to the magnitude or rate of unloading or time spent unloaded in the carotid artery (r = -0.32, -0.07 and 0.06, P = 0.25, 0.81 and 0.85). In contrast, in middle-aged men, the OP was not related to either the magnitude or rate of unloading or time spent unloaded in the aortic (r = 0.22, 0.21 and 0.27, P = 0.41, 0.43 and 031) or carotid artery (r = 0.48, 0.28 and -0.01, P = 0.06, 0.25 and 0.98). In conclusion, in young men, aortic unloading mechanics may play a role in determining the vascular sympathetic baroreflex OP. In contrast, in middle-aged men, barosensory vessel unloading mechanics do not appear to determine the vascular sympathetic baroreflex OP, and therefore do not contribute to age-related arterial baroreflex resetting and increased resting MSNA.
KEYWORDS: muscle sympathetic nerve activity; barosensory vessel unloading mechanics; healthy ageing; sympathetic nervous system; baroreflex
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NEW AND NOTEWORTHY
We assessed the influence of barosensory vessel mechanics (magnitude and rate of unloading and time spent unloaded) as a surrogate for baroreceptor unloading.
In young men, aortic unloading mechanics are important in regulating the operating point of the vascular sympathetic baroreflex, whereas in middle-aged men, these arterial mechanics do not influence this operating point.
The age-related increase in resting muscle sympathetic nerve activity does not appear to be driven by altered baroreceptor input from stiffer barosensory vessels.
Journal/conference proceeding
American Journal of Physiology - Heart and Circulatory Physiology;
Citation
Lord, R.N., Wakeham, D.J., Pugh, C.J., Simpson, L.L., Talbot, J.S., Lodge, F.M., Curry, B.A., Dawkins, T.G., Shave, R.E. and Moore, J.P., (2020) 'The influence of barosensory vessel mechanics on the vascular sympathetic baroreflex: insights into ageing and blood pressure homeostasis', American Journal of Physiology-Heart and Circulatory Physiology.
Description
Article published in American Journal of Physiology - Heart and Circulatory Physiology on 10 July 2020, available at: https://doi.org/10.1152/ajpheart.00265.2020.
Sponsorship
Cardiff Metropolitan University (Grant ID: Cardiff Metropolian (Internal))
Collections
- Sport Research Groups [1089]
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