SIMULTANEOUS WIRELESS MEASUREMENT OF BLOOD PRESSURE AND SYMPATHETIC NERVE ACTIVITY - A System for Investigating Neural Control Mechanisms in Long Term Blood Pressure Regulation

2008 ◽  
Keyword(s):  
Blood Pressure ◽  
Sympathetic Nerve ◽  
Neural Control ◽  
Sympathetic Nerve Activity ◽  
Blood Pressure Regulation ◽  
Control Mechanisms ◽  
Pressure Regulation ◽  
Nerve Activity ◽  
Wireless Measurement

Sex differences in dynamic blood pressure regulation: beat-by-beat responses to muscle sympathetic nerve activity

2020 ◽  
Vol 319 (3) ◽  
pp. H531-H538 ◽  
Author(s):  
Yasmine Coovadia ◽  
Tessa E. Adler ◽  
Craig D. Steinback ◽  
Graham M. Fraser ◽  
Charlotte W. Usselman
Keyword(s):  
Blood Pressure ◽  
Sex Differences ◽  
Young Women ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Blood Pressure Regulation ◽  
Sympathetic Outflow ◽  
Pressure Regulation ◽  
Nerve Activity

We demonstrate that during acute sympathoinhibition, women demonstrate more sustained increases in blood pressure following sympathetic bursts of activity than men. Likewise, during prolonged sympathetic quiescence, blood pressure is less labile in women than men. This suggests that lower overall blood pressure in young women may not be mediated by smaller beat-by-beat changes in blood pressure in response to sympathetic outflow but may instead be mediated by a lower frequency of sympathetic bursts.

Sympathetic responses to vestibular activation in humans

2008 ◽  
Vol 294 (3) ◽  
pp. R681-R688 ◽  
Author(s):  
Jason R. Carter ◽  
Chester A. Ray
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Blood Pressure Regulation ◽  
Otolith Organs ◽  
Pressure Regulation ◽  
Nerve Activity ◽  
Arterial Blood ◽  
Vestibulosympathetic Reflex

Activation of sympathetic neural traffic via the vestibular system is referred to as the vestibulosympathetic reflex. Investigations of the vestibulosympathetic reflex in humans have been limited to the past decade, and the importance of this reflex in arterial blood pressure regulation is still being determined. This review provides a summary of sympathetic neural responses to various techniques used to engage the vestibulosympathetic reflex. Studies suggest that activation of the semicircular canals using caloric stimulation and yaw rotation do not modulate muscle sympathetic nerve activity (MSNA) or skin sympathetic nerve activity (SSNA). In contrast, activation of the otolith organs appear to alter MSNA, but not SSNA. Specifically, head-down rotation and off-vertical axis rotation increase MSNA, while sinusoidal linear accelerations decrease MSNA. Galvanic stimulation, which results in a nonspecific activation of the vestibule, appears to increase MSNA if the mode of delivery is pulse trained. In conclusion, evidence strongly supports the existence of a vestibulosympathetic reflex in humans. Furthermore, attenuation of the vestibulosympathetic reflex is coupled with a drop in arterial blood pressure in the elderly, suggesting this reflex may be important in human blood pressure regulation.

scholarly journals Muscle sympathetic nerve activity and volume-regulating factors in healthy pregnant and nonpregnant women

2017 ◽  
Vol 313 (4) ◽  
pp. H782-H787 ◽  
Author(s):  
Nisha Charkoudian ◽  
Charlotte W. Usselman ◽  
Rachel J. Skow ◽  
Jeffery S. Staab ◽  
Colleen G. Julian ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Plasma Osmolality ◽  
Plasma Renin ◽  
Renin Activity ◽  
Pressure Regulation ◽  
Nerve Activity ◽  
In Pregnancy

Healthy, normotensive human pregnancies are associated with striking increases in both plasma volume and vascular sympathetic nerve activity (SNA). In nonpregnant humans, volume-regulatory factors including plasma osmolality, vasopressin, and the renin-angiotensin-aldosterone system have important modulatory effects on control of sympathetic outflow. We hypothesized that pregnancy would be associated with changes in the relationships between SNA (measured as muscle SNA) and volume-regulating factors, including plasma osmolality, plasma renin activity, and arginine vasopressin (AVP). We studied 46 healthy, normotensive young women (23 pregnant and 23 nonpregnant). We measured SNA, arterial pressure, plasma osmolality, plasma renin activity, AVP, and other volume-regulatory factors in resting, semirecumbent posture. Pregnant women had significantly higher resting SNA (38 ± 12 vs. 23 ± 6 bursts/min in nonpregnant women), lower osmolality, and higher plasma renin activity and aldosterone (all P < 0.05). Group mean values for AVP were not different between groups [4.64 ± 2.57 (nonpregnant) vs. 5.17 ± 2.03 (pregnant), P > 0.05]. However, regression analysis detected a significant relationship between individual values for SNA and AVP in pregnant ( r = 0.71, P < 0.05) but not nonpregnant women ( r = 0.04). No relationships were found for other variables. These data suggest that the link between AVP release and resting SNA becomes stronger in pregnancy, which may contribute importantly to blood pressure regulation in healthy women during pregnancy. NEW & NOTEWORTHY Sympathetic nerve activity and blood volume are both elevated during pregnancy, but blood pressure is usually normal. Here, we identified a relationship between vasopressin and sympathetic nerve activity in pregnant but not nonpregnant women. This may provide mechanistic insights into blood pressure regulation in normal pregnancy and in pregnancy-related hypertension.

scholarly journals Sex-specific computational models for blood pressure regulation in the rat

2020 ◽  
Vol 318 (4) ◽  
pp. F888-F900
Author(s):  
Sameed Ahmed ◽  
Anita T. Layton
Keyword(s):  
Blood Pressure ◽  
Computational Models ◽  
Sympathetic Nerve Activity ◽  
Blood Pressure Regulation ◽  
Female Rats ◽  
Pressure Regulation ◽  
Nerve Activity ◽  
Renal Sympathetic Nerve Activity ◽  
Sodium Handling ◽  
Renal Sympathetic

In the past decades, substantial effort has been devoted to the development of computational models of the cardiovascular system. Some of these models simulate blood pressure regulation in humans and include components of the circulatory, renal, and neurohormonal systems. Although such human models are intended to have clinical value in that they can be used to assess the effects and reveal mechanisms of hypertensive therapeutic treatments, rodent models would be more useful in assisting the interpretation of animal experiments. Also, despite well-known sexual dimorphism in blood pressure regulation, almost all published models are gender neutral. Given these observations, the goal of this project is to develop the first computational models of blood pressure regulation for male and female rats. The resulting sex-specific models represent the interplay among cardiovascular function, renal hemodynamics, and kidney function in the rat; they also include the actions of the renal sympathetic nerve activity and the renin-angiotensin-aldosterone system as well as physiological sex differences. We explore mechanisms responsible for blood pressure and renal autoregulation and notable sexual dimorphism. Model simulations suggest that fluid and sodium handling in the kidney of female rats, which differs significantly from males, may contribute to their observed lower salt sensitivity as compared with males. Additionally, model simulations highlight sodium handling in the kidney and renal sympathetic nerve activity sensitivity as key players in the increased resistance of females to angiotensin II-induced hypertension as compared with males.

Neural control of muscle blood flow during exercise

2004 ◽  
Vol 97 (2) ◽  
pp. 731-738 ◽  
Author(s):  
Gail D. Thomas ◽  
Steven S. Segal
Keyword(s):  
Blood Pressure ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Sympathetic Nerve ◽  
Neural Control ◽  
Sympathetic Nerve Activity ◽  
Muscle Blood Flow ◽  
Nerve Activity ◽  
Arterial Blood

Activation of skeletal muscle fibers by somatic nerves results in vasodilation and functional hyperemia. Sympathetic nerve activity is integral to vasoconstriction and the maintenance of arterial blood pressure. Thus the interaction between somatic and sympathetic neuroeffector pathways underlies blood flow control to skeletal muscle during exercise. Muscle blood flow increases in proportion to the intensity of activity despite concomitant increases in sympathetic neural discharge to the active muscles, indicating a reduced responsiveness to sympathetic activation. However, increased sympathetic nerve activity can restrict blood flow to active muscles to maintain arterial blood pressure. In this brief review, we highlight recent advances in our understanding of the neural control of the circulation in exercising muscle by focusing on two main topics: 1) the role of motor unit recruitment and muscle fiber activation in generating vasodilator signals and 2) the nature of interaction between sympathetic vasoconstriction and functional vasodilation that occurs throughout the resistance network. Understanding how these control systems interact to govern muscle blood flow during exercise leads to a clear set of specific aims for future research.

What sets the long-term level of sympathetic nerve activity: is there a role for arterial baroreceptors?

2004 ◽  
Vol 286 (1) ◽  
pp. R1-R12 ◽  
Author(s):  
Simon C. Malpas
Keyword(s):  
Blood Pressure ◽  
Time Scales ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
New Technologies ◽  
Nerve Activity ◽  
Arterial Baroreceptors ◽  
Experimental Approaches ◽  
Short Time

Much of our knowledge of the influence of the sympathetic nervous system on the control of blood pressure is built on experimental approaches that focus very much on time scales <24 h. Although direct recordings of sympathetic nerve activity (SNA) over short time scales provide important information, it is difficult to place their relevance over the longer term where the development of chronic changes in blood pressure are likely to be a mixture of hormonal, renal, and neural influences. Recently new experimental approaches are now revealing a possible role for arterial baroreceptors in the chronic regulation of SNA. These studies reveal that chronic increases in blood pressure are associated with chronic changes in SNA that may be due to nonresetting of the blood pressure-SNA baroreflex relationship. This review discusses the implications of such information, highlighting new technologies for long-term recording of SNA that appear to hold much promise for revealing the role of SNA to the kidney for the long-term control of blood pressure.

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