Vagally mediated low pressure baroreflex evokes biphasic changes in sympathetic nerve activity and resets the arterial baroreflex (1169.12)

We tested the hypothesis that orthostatic stress would modulate the arterial baroreflex (ABR)-mediated beat-by-beat control of muscle sympathetic nerve activity (MSNA) in humans. In 12 healthy subjects, ABR control of MSNA (burst incidence, burst strength, and total activity) was evaluated by analysis of the relation between beat-by-beat spontaneous variations in diastolic blood pressure (DAP) and MSNA during supine rest (CON) and at two levels of lower body negative pressure (LBNP: −15 and −35 mmHg). At −15 mmHg LBNP, the relation between burst incidence (bursts per 100 heartbeats) and DAP showed an upward shift from that observed during CON, but the further shift seen at −35 mmHg LBNP was only marginal. The relation between burst strength and DAP was shifted upward at −15 mmHg LBNP (vs. CON) and further shifted upward at −35 mmHg LBNP. At −15 mmHg LBNP, the relation between total activity and DAP was shifted upward from that obtained during CON and further shifted upward at −35 mmHg LBNP. These results suggest that ABR control of MSNA is modulated during orthostatic stress and that the modulation is different between a mild (nonhypotensive) and a moderate (hypotensive) level of orthostatic stress.

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Time-dependent modulation of arterial baroreflex control of muscle sympathetic nerve activity during isometric exercise in humans

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00847.2005 ◽

2006 ◽

Vol 290 (4) ◽

pp. H1419-H1426 ◽

Cited By ~ 42

Author(s):

Masashi Ichinose ◽

Mitsuru Saito ◽

Narihiko Kondo ◽

Takeshi Nishiyasu

Keyword(s):

Sympathetic Nerve ◽

Sympathetic Nerve Activity ◽

Muscle Sympathetic Nerve Activity ◽

Isometric Exercise ◽

Time Dependent ◽

Operating Pressure ◽

Dependent Manner ◽

Arterial Baroreflex ◽

Isometric Handgrip ◽

Nerve Activity

We investigated the time-dependent modulation of arterial baroreflex (ABR) control of muscle sympathetic nerve activity (MSNA) that occurs during isometric handgrip exercise (IHG). Thirteen healthy subjects performed a 3-min IHG at 30% maximal voluntary contraction, which was followed by a period of imposed postexercise muscle ischemia (PEMI). The ABR control of MSNA (burst incidence and strength and total activity) was evaluated by analyzing the relationship between spontaneous variations in diastolic arterial pressure (DAP) and MSNA during supine rest, at each minute of IHG, and during PEMI. We found that 1) the linear relations between DAP and MSNA variables were shifted progressively rightward until the third minute of IHG (IHG3); 2) 2 min into IHG (IHG2), the DAP-MSNA relations were shifted upward and were shifted further upward at IHG3; 3) the sensitivity of the ABR control of total MSNA was increased at IHG2 and increased further at IHG3; and 4) during PEMI, the ABR operating pressure was slightly higher than at IHG2, and the sensitivity of the control of total MSNA was the same as at IHG2. During PEMI, the DAP-burst strength and DAP-total MSNA relations were shifted downward from the IHG3 level to the IHG2 level, whereas the DAP-burst incidence relation remained at the IHG3 level. These results indicate that during IHG, ABR control of MSNA is modulated in a time-dependent manner. We suggest that this modulation of ABR function is one of the mechanisms underlying the progressive increase in blood pressure and MSNA during the course of isometric exercise.

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Low Pressure Baroreflex Evokes Biphasic Change in Sympathetic Nerve Activity through Vagal Nerve

Journal of Cardiac Failure ◽

10.1016/j.cardfail.2013.08.420 ◽

2013 ◽

Vol 19 (10) ◽

pp. S161

Author(s):

Yasuhiro Oga ◽

Takuya Kishi ◽

Keita Saku ◽

Takamori Kakino ◽

Masataka Ikeda ◽

...

Keyword(s):

Sympathetic Nerve ◽

Sympathetic Nerve Activity ◽

Low Pressure ◽

Vagal Nerve ◽

Nerve Activity

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Acute effects of arterial baroreflex on sympathetic nerve activity and plasma norepinephrine concentration

Autonomic Neuroscience ◽

10.1016/j.autneu.2014.10.016 ◽

2014 ◽

Vol 186 ◽

pp. 62-68 ◽

Cited By ~ 6

Author(s):

Toru Kawada ◽

Tsuyoshi Akiyama ◽

Shuji Shimizu ◽

Yusuke Sata ◽

Michael J. Turner ◽

...

Keyword(s):

Sympathetic Nerve ◽

Sympathetic Nerve Activity ◽

Plasma Norepinephrine ◽

Arterial Baroreflex ◽

Acute Effects ◽

Nerve Activity ◽

Norepinephrine Concentration

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Water drinking enhances the gain of arterial baroreflex control of muscle sympathetic nerve activity in healthy humans

The FASEB Journal ◽

10.1096/fasebj.27.1_supplement.1118.26 ◽

2013 ◽

Vol 27 (S1) ◽

Author(s):

Lauro C Vianna ◽

Igor A Fernandes ◽

Daniel G Martinez ◽

Bruno M Silva ◽

Paul J Fadel ◽

...

Keyword(s):

Sympathetic Nerve ◽

Sympathetic Nerve Activity ◽

Muscle Sympathetic Nerve Activity ◽

Arterial Baroreflex ◽

Nerve Activity ◽

Baroreflex Control ◽

Water Drinking ◽

Healthy Humans

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Baroreflex modulation of sympathetic nerve activity to muscle in heat-stressed humans

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00337.2001 ◽

2002 ◽

Vol 282 (1) ◽

pp. R252-R258 ◽

Cited By ~ 45

Author(s):

Jian Cui ◽

Thad E. Wilson ◽

Craig G. Crandall

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Heat Stress ◽

Sympathetic Nerve ◽

Sympathetic Nerve Activity ◽

Whole Body ◽

Arterial Baroreflex ◽

Nerve Activity ◽

Arterial Blood ◽

The Relationship

To identify whether whole body heating alters arterial baroreflex control of muscle sympathetic nerve activity (MSNA), MSNA and beat-by-beat arterial blood pressure were recorded in seven healthy subjects during acute hypotensive and hypertensive stimuli in both normothermic and heat stress conditions. Whole body heating significantly increased sublingual temperature ( P < 0.01), MSNA ( P < 0.01), heart rate ( P< 0.01), and skin blood flow ( P < 0.001), whereas mean arterial blood pressure did not change significantly ( P > 0.05). During both normothermic and heat stress conditions, MSNA increased and then decreased significantly when blood pressure was lowered and then raised via intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure during heat stress (−128.3 ± 13.9 U · beats−1 · mmHg−1) was similar ( P = 0.31) with normothermia (−140.6 ± 21.1 U · beats−1 · mmHg−1). Moreover, no significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. These data suggest that arterial baroreflex modulation of MSNA and heart rate are not altered by whole body heating, with the exception of an upward shift of these baroreflex curves to accommodate changes in these variables that occur with whole body heating.

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