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- Barnes, J. N., et al.
(author)
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Aging enhances autonomic support of blood pressure in women
- 2014
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In: Hypertension. - 0194-911X .- 1524-4563. ; 63:2, s. 303-308
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Journal article (peer-reviewed)abstract
- The autonomic nervous system plays a central role in both acute and chronic blood pressure regulation in humans. The activity of the sympathetic branch of the autonomic nervous system is positively associated with peripheral resistance, an important determinant of mean arterial pressure in men. In contrast, there is no association between sympathetic nerve activity and peripheral resistance in women before menopause, yet a positive association after menopause. We hypothesized that autonomic support of blood pressure is higher after menopause in women. We examined the effect of ganglionic blockade on arterial blood pressure and how this relates to baseline muscle sympathetic nerve activity in 12 young (25±1 years) and 12 older postmenopausal (61±2 years) women. The women were studied before and during autonomic blockade using trimethaphan camsylate. At baseline, muscle sympathetic nerve activity burst frequency and burst incidence were higher in the older women (33±3 versus 15±1 bursts/min; 57±5 versus 25±2 bursts/100 heartbeats, respectively; P<0.05). Muscle sympathetic nerve activity bursts were abolished by trimethaphan within minutes. Older women had a greater decrease in mean arterial pressure (-29±2 versus-9±2 mm Hg; P<0.01) and total peripheral resistance (-10±1 versus-5±1 mm Hg/L per minute; P<0.01) during trimethaphan. Baseline muscle sympathetic nerve activity was associated with the decrease in mean arterial pressure during trimethaphan (r=-0.74; P<0.05). In summary, our results suggest that autonomic support of blood pressure is greater in older women compared with young women and that elevated sympathetic nerve activity in older women contributes importantly to the increased incidence of hypertension after menopause. © 2013 American Heart Association, Inc.
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| 3. |
- Peinado, A. B., et al.
(author)
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Neural control of blood pressure in women: differences according to age
- 2017
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In: Clinical Autonomic Research. - : Springer Science and Business Media LLC. - 0959-9851 .- 1619-1560. ; 27:3, s. 157-165
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Journal article (peer-reviewed)abstract
- Purpose The blood pressure "error signal'' represents the difference between an individual's mean diastolic blood pressure and the diastolic blood pressure at which 50% of cardiac cycles are associated with a muscle sympathetic nerve activity burst (the "T50''). In this study we evaluated whether T50 and the error signal related to the extent of change in blood pressure during autonomic blockade in young and older women, to study potential differences in sympathetic neural mechanisms regulating blood pressure before and after menopause. Methods We measured muscle sympathetic nerve activity and blood pressure in 12 premenopausal (25 +/- 1 years) and 12 postmenopausal women (61 +/- 2 years) before and during complete autonomic blockade with trimethaphan camsylate. Results At baseline, young women had a negative error signal (-8 +/- 1 versus 2 +/- 1 mmHg, p < 0.001; respectively) and lower muscle sympathetic nerve activity (15 +/- 1 versus 33 +/- 3 bursts/min, p < 0.001; respectively) than older women. The change in diastolic blood pressure after autonomic blockade was associated with baseline T50 in older women (r = -0.725, p = 0.008) but not in young women (r = -0.337, p = 0.29). Women with the most negative error signal had the lowest muscle sympathetic nerve activity in both groups (young: r = 0.886, p < 0.001; older: r = 0.870, p < 0.001). Conclusions Our results suggest that there are differences in baroreflex control of muscle sympathetic nerve activity between young and older women, using the T50 and error signal analysis. This approach provides further information on autonomic control of blood pressure in women.
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