The influence of barosensory vessel mechanics on the vascular sympathetic baroreflex: Insights into ageing and blood pressure homeostasis
Pugh, Christopher J. A.
American Physiological Society
MetadataShow full item record
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 Page Break 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.
American Journal of Physiology - Heart and Circulatory Physiology;
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.
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.
Cardiff Metropolitan University (Grant ID: Cardiff Metropolian (Internal))
- Sport Research Groups 
Showing items related by title, author, subject and abstract.
Wakeham, Denis; Lord, Rachel; Talbot, Jack; Lodge, Freya; Curry, Bryony; Dawkins, Tony; Simpson, Lydia; Shave, Rob; Pugh, Christopher J. A.; Moore, Jonathan (American Physiological Society, 2019-05-03)This study focussed on the influence of habitual endurance exercise training (i.e. committed runner or non-runner) on the regulation of muscle sympathetic nerve activity (MSNA) and arterial pressure in middle-aged (50 to ...
Evidence for a physiological role of pulmonary arterial baroreceptors in sympathetic neural activation in healthy humans Simpson, Lydia; Meah, Victoria L.; Steele, Andrew; Thapamagar, Suman; Gasho, Chris; Anholm, James; Drane, Aimee L.; Dawkins, Tony; Busch, Stephen; Oliver, Samuel; Lawley, Justin; Tymko, Mike; Ainslie, Philip; Steinback, Craig; Stembridge, Mike; Moore, Jonathan (Wiley, 2020-01-24)In animal models, distension of baroreceptors located in the pulmonary artery induces a reflex increase in sympathetic outflow; however, this has not been examined in humans. Therefore, we investigated whether reductions ...
Baroreflex control of sympathetic vasomotor activity and resting arterial pressure at high altitude: insight from Lowlanders and Sherpa Simpson, Lydia; Busch, Stephen; Oliver, Samuel; Ainslie, Philip; Stembridge, Mike; Steinback, Craig; Moore, Jonathan (Wiley, 2019-03-20)Exposure to high altitude (HA) is characterized by heightened muscle sympathetic neural activity (MSNA); however, the effect on arterial baroreflex control of MSNA is unknown. Furthermore, arterial baroreflex control at ...