Blunted increases in leg vascular conductance to carotid baroreflex activation in young women

2011 ◽  
Vol 163 (1-2) ◽  
pp. 44-45
Author(s):  
L.C. Vianna ◽  
A. Kim ◽  
S.T. Fairfax ◽  
P.J. Fadel
Keyword(s):  
Young Women ◽  
Vascular Conductance ◽  
Carotid Baroreflex

scholarly journals Effect of aging on carotid baroreflex control of blood pressure and leg vascular conductance in women

2014 ◽  
Vol 306 (10) ◽  
pp. H1417-H1425 ◽  
Author(s):  
Daniel P. Credeur ◽  
Seth W. Holwerda ◽  
Leryn J. Boyle ◽  
Lauro C. Vianna ◽  
Areum K. Jensen ◽  
...  
Keyword(s):  
Older Women ◽  
Young Women ◽  
Vascular Changes ◽  
Vascular Conductance ◽  
Response Latencies ◽  
Baroreflex Control ◽  
Age Related ◽  
Carotid Baroreflex ◽  
Duplex Doppler ◽  
Neck Pressure

Recent work suggests that β-adrenergic vasodilation offsets α-adrenergic vasoconstriction in young women, but this effect is lost after menopause. Given these age-related vascular changes, we tested the hypothesis that older women would exhibit a greater change in vascular conductance following baroreflex perturbation compared with young women. In 10 young (21 ± 1 yr) and 10 older (62 ± 2 yr) women, mean arterial pressure (MAP; Finometer), heart rate (HR), cardiac output (CO; Modelflow), total vascular conductance (TVC), and leg vascular conductance (LVC, duplex-Doppler ultrasound) were continuously measured in response to 5-s pulses of neck suction (NS; −60 Torr) and neck pressure (NP; +40 Torr) to simulate carotid hypertension and hypotension, respectively. Following NS, decreases in MAP were similar between groups; however, MAP peak response latency was slower in older women ( P < 0.05). Moreover, at the time of peak MAP, increases in LVC (young, −11.5 ± 3.9%LVC vs. older, +19.1 ± 7.0%LVC; P < 0.05) and TVC were greater in older women, whereas young women exhibited larger decreases in HR and CO (young, −10 ± 3% CO vs. older, +0.8 ± 2% CO; P < 0.05). Following NP, increases in MAP were blunted (young, +14 ± 1 mmHg vs. older, +8 ± 1 mmHg; P < 0.05) in older women, whereas MAP response latencies were similar. Interestingly, decreases in LVC and TVC were similar between groups, but HR and CO (young, +7.0 ± 2% CO vs. older, −4.0 ± 2% CO; P < 0.05) responses were attenuated in older women. These findings suggest that older women have greater reliance on vascular conductance to modulate MAP via carotid baroreflex, whereas young women rely more on cardiac responsiveness. Furthermore, older women demonstrate a blunted ability to increase MAP to hypotensive stimuli.

scholarly journals Sex differences in carotid baroreflex control of arterial blood pressure in humans: relative contribution of cardiac output and total vascular conductance

2011 ◽  
Vol 301 (6) ◽  
pp. H2454-H2465 ◽  
Author(s):  
Areum Kim ◽  
Shekhar H. Deo ◽  
Lauro C. Vianna ◽  
George M. Balanos ◽  
Doreen Hartwich ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Sex Differences ◽  
Cardiac Output ◽  
Young Women ◽  
Vascular Conductance ◽  
Baroreflex Control ◽  
Relative Contribution ◽  
Arterial Blood ◽  
Carotid Baroreflex ◽  
Neck Pressure

It is presently unknown whether there are sex differences in the magnitude of blood pressure (BP) responses to baroreceptor perturbation or if the relative contribution of cardiac output (CO) and total vascular conductance (TVC) to baroreflex-mediated changes in BP differs in young women and men. Since sympathetic vasoconstrictor tone is attenuated in women, we hypothesized that carotid baroreflex-mediated BP responses would be attenuated in women by virtue of a blunted vascular response (i.e., an attenuated TVC response). BP, heart rate (HR), and stroke volume were continuously recorded during the application of 5-s pulses of neck pressure (NP; carotid hypotension) and neck suction (NS; carotid hypertension) ranging from +40 to −80 Torr in women ( n = 20, 21 ± 0.5 yr) and men ( n = 20, 21 ± 0.4 yr). CO and TVC were calculated on a beat-to-beat basis. Women demonstrated greater depressor responses to NS (e.g., −60 Torr, −17 ± 1%baseline in women vs. −11 ± 1%baseline in men, P < 0.05), which were driven by augmented decreases in HR that, in turn, contributed to larger reductions in CO (−60 Torr, −15 ± 2%baseline in women vs. −6 ± 2%baseline in men, P < 0.05). In contrast, pressor responses to NP were similar in women and men (e.g., +40 Torr, +14 ± 2%baseline in women vs. +10 ± 1%baseline in men, P > 0.05), with TVC being the primary mediating factor in both groups. Our findings indicate that sex differences in the baroreflex control of BP are evident during carotid hypertension but not carotid hypotension. Furthermore, in contrast to our hypothesis, young women exhibited greater BP responses to carotid hypertension by virtue of a greater cardiac responsiveness.

scholarly journals Carotid baroreflex responses to simulated hypotension are blunted during passive whole‐body heat stress in young women

2018 ◽  
Vol 32 (S1) ◽  
Author(s):  
Dustin Allen ◽  
Mu Huang ◽  
Kelly Lenz ◽  
Ursa Bezan Petric ◽  
David Keller ◽  
...  
Keyword(s):  
Heat Stress ◽  
Young Women ◽  
Whole Body ◽  
Carotid Baroreflex ◽  
Whole Body Heat Stress ◽  
Body Heat

Carotid baroreflex control of leg vascular conductance at rest and during exercise

2003 ◽  
Vol 94 (2) ◽  
pp. 542-548 ◽  
Author(s):  
David M. Keller ◽  
Wendy L. Wasmund ◽  
D. Walter Wray ◽  
Shigehiko Ogoh ◽  
Paul J. Fadel ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Vascular Tone ◽  
Knee Extension ◽  
Vascular Conductance ◽  
Baroreflex Control ◽  
Carotid Baroreflex ◽  
Neck Pressure ◽  
Induced Changes ◽  
Knee Extension Exercise ◽  
Rest And Exercise

We sought to test the hypothesis that the carotid baroreflex (CBR) alters mean leg blood flow (LBF) and leg vascular conductance (LVC) at rest and during exercise. In seven men and one woman, 25 ± 2 (SE) yr of age, CBR control of LBF and LVC was determined at rest and during steady-state one-legged knee extension exercise at ∼65% peak O2 uptake. The application of 5-s pulses of +40 Torr neck pressure and −60 Torr neck suction significantly altered mean arterial pressure (MAP) and LVC both at rest and during exercise. CBR-mediated changes in MAP were similar between rest and exercise ( P > 0.05). However, CBR-mediated decreases in LVC (%change) to neck pressure were attenuated in the exercising leg (16.4 ± 1.6%) compared with rest (33 ± 2.1%) and the nonexercising leg (23.7 ± 1.9%) ( P < 0.01). These data suggest CBR control of blood pressure is partially mediated by changes in leg vascular tone both at rest and during exercise. Furthermore, despite alterations in CBR-induced changes in LVC during exercise, CBR control of blood pressure was well maintained.

scholarly journals Impaired carotid baroreflex control of arterial blood pressure in multiple sclerosis

2016 ◽  
Vol 116 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Mu Huang ◽  
Dustin R. Allen ◽  
David M. Keller ◽  
Paul J. Fadel ◽  
Elliot M. Frohman ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Blood Pressure ◽  
Heart Rate ◽  
Cardiovascular Responses ◽  
Vascular Conductance ◽  
Baroreflex Control ◽  
Arterial Blood ◽  
Carotid Baroreflex ◽  
Relapsing Remitting ◽  
Neck Pressure

Multiple sclerosis (MS), a progressive neurological disease, can lead to impairments in the autonomic control of cardiovascular function. We tested the hypothesis that individuals with relapsing-remitting MS ( n = 10; 7 females, 3 males; 13 ± 4 yr from diagnosis) exhibit impaired carotid baroreflex control of blood pressure and heart rate compared with sex, age, and body weight-matched healthy individuals (CON: n = 10; 7 females, 3 males). At rest, 5-s trials of neck pressure (NP; +40 Torr) and neck suction (NS; −60 Torr) were applied to simulate carotid hypotension and hypertension, respectively, while mean arterial pressure (MAP; finger photoplethysmography), heart rate (HR), cardiac output (CO; Modelflow), and total vascular conductance (TVC) were continuously measured. In response to NP, there was a blunted increase in peak MAP responses (MS: 5 ± 2 mmHg) in individuals with MS compared with healthy controls (CON: 9 ± 3 mmHg; P = 0.005), whereas peak HR responses were not different between groups. At the peak MAP response to NP, individuals with MS demonstrated an attenuated decrease in TVC (MS, −10 ± 4% baseline vs. CON, −15 ± 4% baseline, P = 0.012), whereas changes in CO were similar between groups. Following NS, all cardiovascular responses (i.e., nadir MAP and HR and percent changes in CO and TVC) were not different between MS and CON groups. These data suggest that individuals with MS have impaired carotid baroreflex control of blood pressure via a blunted vascular conductance response resulting in a diminished ability to increase MAP in response to a hypotensive challenge.

Muscle metaboreflex modulates the arterial baroreflex dynamic effects on peripheral vascular conductance in humans

2005 ◽  
Vol 288 (4) ◽  
pp. H1532-H1538 ◽  
Author(s):  
Masashi Ichinose ◽  
Takeshi Nishiyasu
Keyword(s):  
Dynamic Effect ◽  
Voluntary Contraction ◽  
Dynamic Responses ◽  
Arterial Baroreflex ◽  
Peripheral Vascular ◽  
Vascular Conductance ◽  
Muscle Metaboreflex ◽  
Arterial Blood ◽  
Carotid Baroreflex ◽  
Neck Pressure

We aimed to investigate the interaction between the arterial baroreflex and muscle metaboreflex [as reflected by alterations in the dynamic responses shown by leg blood flow (LBF: by the ultrasound Doppler method), leg vascular conductance (LVC), mean arterial blood pressure (MAP), and heart rate (HR)] in humans. In 12 healthy subjects (10 men and 2 women), who performed sustained 1-min handgrip exercise at 50% maximal voluntary contraction followed immediately by an imposed postexercise muscle ischemia (PEMI), 5-s periods of neck pressure (NP; 50 mmHg) or neck suction (NS; −60 mmHg) were used to evaluate carotid baroreflex function both at rest (Con) and during PEMI. First, the decreases in LVC and LBF and the augmentation of MAP elicited by NP were all greater during PEMI than in Con (ΔLVC, −1.2 ± 0.2 vs. −1.9 ± 0.2 ml·min−1·mmHg−1; ΔLBF, −97.3 ± 11.2 vs. −177.0 ± 21.8 ml/min; ΔMAP, 6.7 ± 1.2 vs. 11.5 ± 1.4 mmHg, Con vs. PEMI; each P < 0.05). Second, in Con, NS significantly increased both LVC and LBF (ΔLVC, 0.9 ± 0.2 ml·min−1·mmHg−1; ΔLBF, 46.6 ± 9.8 ml/min; significant change from baseline: each P < 0.05), and, whereas during PEMI no significant increases in LVC and LBF occurred during NS itself (ΔLVC, 0.2 ± 0.1 ml·min−1·mmHg−1; ΔLBF, 10.8 ± 9.6 ml/min; each P > 0.05), a decrease was evident in each parameters at 5 s after the cessation of NS. Third, during PEMI, the decrease in MAP elicited by NS was smaller (ΔMAP, −8.4 ± 1.0 vs. −5.8 ± 0.4 mmHg, Con vs. PEMI; P < 0.05), and it recovered to its initial level more quickly after NS (vs. Con). Finally, however, the HR responses to NS and NP were not different between PEMI and Con. These results suggest that during muscle metaboreflex activation in humans, the arterial baroreflex dynamic effect on peripheral vascular conductance is modulated, as exemplified by 1) an augmentation of the NP-induced LVC decrease, and 2) a loss of the NS-induced LVC increase.

CAROTID BAROREFLEX CONTROL OF CARDIAC OUTPUT AND REGIONAL VASCULAR CONDUCTANCE DURING DYNAMIC EXERCISE

2003 ◽  
Vol 35 (Supplement 1) ◽  
pp. S109
Author(s):  
S Ogoh ◽  
P J. Fadel ◽  
P Nissen ◽  
O Jans ◽  
C Selmer ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Dynamic Exercise ◽  
Vascular Conductance ◽  
Baroreflex Control ◽  
Carotid Baroreflex
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