scholarly journals Recent Insights into Carotid Baroreflex Function in Humans Using the Variable Pressure Neck Chamber

2003 ◽  
Vol 88 (6) ◽  
pp. 671-680 ◽  
Author(s):  
Paul J. Fadel ◽  
Shigehiko Ogoh ◽  
David M. Keller ◽  
Peter B. Raven
1979 ◽  
Vol 237 (2) ◽  
pp. H153-H158 ◽  
Author(s):  
H. I. Chen ◽  
C. Y. Chai ◽  
C. S. Tung ◽  
H. C. Chen

1997 ◽  
Vol 273 (4) ◽  
pp. R1219-R1223 ◽  
Author(s):  
S. Sagawa ◽  
R. Torii ◽  
K. Nagaya ◽  
F. Wada ◽  
Y. Endo ◽  
...  

To examine the baroreflex response in humans during acute high-altitude exposure, the carotid baroreflex cardiac responsiveness was studied using a neck chamber in seven unacclimatized male subjects. Measurements were made in a high-altitude chamber on separate days at sea level and during 1-h exposure at two different altitudes of 3,800 m [partial pressure of oxygen in inspired air (Pi O2 ) = 90 mmHg] and 4,300 m (Pi O2  = 82 mmHg). R-R intervals were plotted against neck chamber pressures, and the baroreceptor response was analyzed by applying a four-parameter sigmoidal logistic function. The baroreceptor response curve shifted downward in either altitude, reflecting a tachycardic response at high altitude, and the magnitude of the shift was greater at 4,300 m than at 3,800 m. There was no change in the sigmoidal parameters at 3,800 m compared with sea level except for a reduction ( P < 0.05) of the minimum R-R interval. At 4,300 m the maximal R-R range, slope coefficient, minimum R-R interval, and maximal gain of the curve decreased significantly ( P < 0.05) compared with sea level values, whereas the centering point of the curve remained unchanged. These results suggest that hypoxia (Pi O2  = 82 mmHg) reduces the sensitivity of carotid baroreflex cardiac response.


2002 ◽  
Vol 34 (5) ◽  
pp. S112
Author(s):  
S Ogoh ◽  
D Keller ◽  
R Vinson ◽  
W Wasmund ◽  
A H. Olivencia-Yurvati ◽  
...  

1979 ◽  
Vol 57 (s5) ◽  
pp. 165s-167s ◽  
Author(s):  
G. Mancia ◽  
G. Leonetti ◽  
G. B. Picotti ◽  
A. Ferrari ◽  
M. D. Galva ◽  
...  

1. Slight decreases and increases in carotid baroreceptor activity were induced in subjects with essential hypertension by slight alterations in carotid transmural pressure (variable pressure neck-chamber technique) in order to obtain limited increases and reductions in sympathetic adrenergic activity. 2. When sympathetic activity was reflexly increased there was a rise in arterial pressure but no significant increase in plasma catecholamines. Likewise when sympathetic activity was reflexly reduced there was a fall in arterial pressure but no significant reduction in plasma catecholamines. 3. Plasma noradrenaline and adrenaline significantly and markedly increased in the same subjects when sympathetic activity was increased by activation of both arterial and low pressure baroreceptor reflexes with tilting. 4. It is suggested that measurements of catecholamines in systemic plasma may reveal marked degrees of sympathetic activation but may not be a sensitive index of more moderate changes in sympathetic tone.


1999 ◽  
Vol 31 (Supplement) ◽  
pp. S224
Author(s):  
S. A. Smith ◽  
R. G. Querry ◽  
K. M. Gallagher ◽  
M. Stromstad ◽  
K. Ide ◽  
...  

2005 ◽  
Vol 37 (Supplement) ◽  
pp. S224
Author(s):  
Stefanos Volianitis ◽  
Thomas Vogelsang ◽  
Niels H. Secher

2016 ◽  
Vol 311 (3) ◽  
pp. H699-H706 ◽  
Author(s):  
Joshua C. Tremblay ◽  
Lindsey M. Boulet ◽  
Michael M. Tymko ◽  
Glen E. Foster

Intermittent hypoxia (IH) occurs in association with obstructive sleep apnea and likely contributes to the pathogenesis of hypertension. The purpose of this study was to examine the putative early adaptations at the level of the peripheral vasculature and carotid baroreflex (CBR) that may promote the development of hypertension. Ten healthy male participants (26 ± 1 yr, BMI = 24 ± 1 kg/m2) were exposed to 6 h of IH (1-min cycles of normoxia and hypoxia) and SHAM in a single-blinded, counterbalanced crossover study design. Ambulatory blood pressure was measured during each condition and the following night. Vascular strain of the carotid and femoral artery, a measure of localized arterial stiffness, and hemodynamic shear patterns in the brachial and femoral arteries were measured during each condition. Brachial artery reactive hyperemia flow-mediated vasodilation was assessed before and after each condition as a measure of endothelial function. CBR function and its control over leg vascular conductance (LVC) were measured after each condition with a variable-pressure neck chamber. Intermittent hypoxia 1) increased nighttime pulse pressure by 3.2 ± 1.3 mmHg, 2) altered femoral but not brachial artery hemodynamics, 3) did not affect brachial artery endothelial function, 4) reduced vascular strain in the carotid and possibly femoral artery, and 5) shifted CBR mean arterial pressure (MAP) to higher MAP while blunting LVC responses to CBR loading. These results suggest limb-specific vascular impairments, reduced vascular strain, and CBR resetting combined with blunted LVC responses are factors in the early pathogenesis of IH-induced development of hypertension.


2018 ◽  
Vol 125 (2) ◽  
pp. 634-641 ◽  
Author(s):  
Shigehiko Ogoh ◽  
Michaël Marais ◽  
Romain Lericollais ◽  
Pierre Denise ◽  
Peter B. Raven ◽  
...  

The aim of the present study was to assess carotid baroreflex (CBR) function during acute changes in otolithic activity in humans. To address this question, we designed a set of experiments to identify the modulatory effects of microgravity on CBR function at a tilt angle of −2°, which was identified to minimize changes in central blood volume during parabolic flight. During parabolic flight at 0 and 1 g, CBR function curves were modeled from the heart rate (HR) and mean arterial pressure (MAP) responses to rapid pulse trains of neck pressure and neck suction ranging from +40 to −80 Torr; CBR control of HR (carotid-HR) and MAP (carotid-MAP) function curves, respectively. The maximal gain of both carotid-HR and carotid-MAP baroreflex function curves were augmented during microgravity compared with 1 g (carotid-HR, −0.53 to −0.80 beats·min−1·mmHg−1, P < 0.05; carotid-MAP, −0.24 to −0.30 mmHg/mmHg, P < 0.05). These findings suggest that parabolic flight-induced acute change of otolithic activity may modify CBR function and identifies that the vestibular system contributes to blood pressure regulation under fluctuations in gravitational forces. NEW & NOTEWORTHY The effect of acute changes in vestibular activity on arterial baroreflex function remains unclear. In the present study, we assessed carotid baroreflex function without changes in central blood volume during parabolic flight, which causes acute changes in otolithic activity. The sensitivity of both carotid heart rate and carotid mean arterial pressure baroreflex function was augmented in microgravity compared with 1 g, suggesting that the vestibular system contributes to blood pressure regulation in humans on Earth.


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