TY - JOUR

T1 - The influence of barosensory vessel mechanics on the vascular sympathetic baroreflex: insights into aging and blood pressure homeostasis

AU - Lord, Rachel

AU - Wakeham, Denis J.

AU - Pugh, Christopher J.A.

AU - Simpson, Lydia

AU - Talbot, Jack

AU - Lodge, Freya M.

AU - Curry, Bryony

AU - Dawkins, Tony

AU - Shave, Rob

AU - Moore, Jonathan

PY - 2020/8/4

Y1 - 2020/8/4

N2 - Changes in the arterial baroreflex arc contribute to elevated sympathetic outflowand altered reflex control of blood pressure with human aging.Using ultrasound and sympathetic microneurography (muscle sympatheticnerve activity, MSNA) we investigated the relationships betweenaortic and carotid artery wall tension (indices of baroreceptoractivation) and the vascular sympathetic baroreflex operating point(OP; MSNA burst incidence) in healthy, normotensive young (n 27,23 3 yr) and middle-aged men (n 22, 55 4 yr). In young men,the OP was positively related to the magnitude and rate of unloadingand 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 ofunloading or time spent unloaded in the carotid artery (r0.32,0.07, and 0.06, P 0.25, 0.81, and 0.85). In contrast, in middleagedmen, the OP was not related to either the magnitude or rate ofunloading or time spent unloaded in the aortic (r 0.22, 0.21, and0.27, P 0.41, 0.43, and 0.31) or carotid artery (r 0.06, 0.28, and0.01; P 0.48, 0.25, and 0.98). In conclusion, in young men, aorticunloading mechanics may play a role in determining the vascularsympathetic baroreflex OP. In contrast, in middle-aged men, barosensoryvessel unloading mechanics do not appear to determine thevascular sympathetic baroreflex OP and, therefore, do not contributeto age-related arterial baroreflex resetting and increased restingMSNA.

AB - Changes in the arterial baroreflex arc contribute to elevated sympathetic outflowand altered reflex control of blood pressure with human aging.Using ultrasound and sympathetic microneurography (muscle sympatheticnerve activity, MSNA) we investigated the relationships betweenaortic and carotid artery wall tension (indices of baroreceptoractivation) and the vascular sympathetic baroreflex operating point(OP; MSNA burst incidence) in healthy, normotensive young (n 27,23 3 yr) and middle-aged men (n 22, 55 4 yr). In young men,the OP was positively related to the magnitude and rate of unloadingand 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 ofunloading or time spent unloaded in the carotid artery (r0.32,0.07, and 0.06, P 0.25, 0.81, and 0.85). In contrast, in middleagedmen, the OP was not related to either the magnitude or rate ofunloading or time spent unloaded in the aortic (r 0.22, 0.21, and0.27, P 0.41, 0.43, and 0.31) or carotid artery (r 0.06, 0.28, and0.01; P 0.48, 0.25, and 0.98). In conclusion, in young men, aorticunloading mechanics may play a role in determining the vascularsympathetic baroreflex OP. In contrast, in middle-aged men, barosensoryvessel unloading mechanics do not appear to determine thevascular sympathetic baroreflex OP and, therefore, do not contributeto age-related arterial baroreflex resetting and increased restingMSNA.

KW - baroreflex

KW - barosensory vessel unloading mechanics

KW - healthy aging

KW - muscle sympathetic nerve activity

KW - sympathetic nervous system

U2 - 10.1152/ajpheart.00265.2020

DO - 10.1152/ajpheart.00265.2020

M3 - Article

VL - 319

SP - H370-H376

JO - American Journal of Physiology - Heart and Circulatory Physiology

JF - American Journal of Physiology - Heart and Circulatory Physiology

SN - 0363-6135

IS - 2

ER -