scholarly journals Exercise hyperemia and vasoconstrictor responses in humans with cystic fibrosis

2005 ◽  
Vol 99 (5) ◽  
pp. 1866-1871 ◽  
Author(s):  
William G. Schrage ◽  
Brad W. Wilkins ◽  
Vicki L. Dean ◽  
John P. Scott ◽  
Nancy K. Henry ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cystic Fibrosis ◽  
Blood Flow ◽  
Forearm Blood Flow ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Pressor Test ◽  
Sympathetic Vasoconstriction ◽  
Exercise Hyperemia ◽  
Forearm Exercise

ATP released from circulating erythrocytes is a potential signal regulating muscle blood flow during exercise (exercise hyperemia), and intravascular ATP appears to blunt sympathetic vasoconstriction during exercise. Erythrocytes from patients with cystic fibrosis (CF) do not release ATP. The goal of the present study was to determine whether increases in forearm blood flow during exercise are blunted in CF patients and whether CF patients exhibit greater vasoconstrictor responsiveness during exercise. Nine control subjects and 10 CF patients who were free of other disease complications (∼96% O2 saturation) performed incremental rhythmic forearm exercise at 5, 10, and 15% of maximum handgrip strength for 21 min (7 min at each workload). We used a cold pressor test to evoke sympathetic vasoconstriction under resting conditions and at each exercise workload. As a control, subjects performed a second exercise bout without the cold pressor test. Continuous brachial artery blood velocity was monitored beat-to-beat, and vessel diameter was assessed by Doppler ultrasound. Artery diameter, as well as blood pressure, heart rate, and O2 saturation, was measured at steady-state exercise and at 1 min into the cold pressor stimulus. Blood pressure and heart rate responses to the forearm exercise and each cold pressor test were similar in both groups ( P > 0.05). Contrary to our hypothesis, forearm blood flow ( P = 0.91) and forearm vascular conductance ( P = 0.82) were similar at rest and at each level of exercise between CF patients and controls. Additionally, there was no difference in the degree of sympathetic vasoconstriction between groups at rest and at each level of exercise ( P = 0.22). Our results suggest that ATP released from the deformation of erythrocytes is not an obligatory signal for exercise hyperemia in human skeletal muscle.

Elevated Plasma Adrenaline Reflects Sympathetic Overactivity and Enhanced α-Adrenoceptor-Mediated Vasoconstriction in Essential Hypertension

1981 ◽  
Vol 61 (s7) ◽  
pp. 161s-164s ◽  
Author(s):  
P. Bolli ◽  
F. W. Amann ◽  
L. Hulthén ◽  
W. Kiowski ◽  
F. R. Bühler
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Essential Hypertension ◽  
Forearm Blood Flow ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Plasma Adrenaline ◽  
Pressor Test ◽  
Normotensive Subjects

1. Stressful sympathetic stimulation (cold pressor test) was applied to 18 patients with essential hypertension and 15 normotensive subjects. Intra-arterial blood pressure, heart rate, plasma adrenaline and noradrenaline concentrations as well as forearm blood flow were measured before and during the cold pressor test; tests were repeated after regional postsynaptic α1-adrenoceptor blockade with prazosin. 2. Under basal conditions mean blood pressure (P < 0.001), heart rate (P < 0.01), forearm blood flow (P < 0.001) as well as adrenaline concentration (P < 0.01), but not noradrenaline, was higher in patients with essential hypertension. 3. During the cold pressor test, mean blood pressure, heart rate, plasma adrenaline and noradrenaline concentrations increased and forearm flow decreased (all P < 0.001). 4. Stress-stimulated plasma adrenaline was higher in essential hypertensive patients than in normotensive subjects (P < 0.01). In the former the stress-induced increase in plasma adrenaline correlated with the increase in mean blood pressure (r = 0.514; P < 0.05). 5. Prazosin increased forearm blood flow more in essential hypertension (P < 0.001). This increase correlated with the resting plasma adrenaline in the hypertensive (r = 0.710; P < 0.001), but not in normotensive, subjects. 6. When the cold pressor test was repeated during postsynaptic α1-adrenoceptor blockade forearm blood flow did not decrease; instead it increased further in both groups (P < 0.05). 7. Thus in essential hypertension elevated plasma adrenaline concentration reflects sympathetic overactivity as also expressed by enhanced α-adrenoceptor-mediated vasoconstriction.

The effect of steady-state CO2 on regional brain blood flow responses to increases in blood pressure via the cold pressor test

2019 ◽  
Vol 222 ◽  
pp. 102581 ◽  
Author(s):  
Brittney A. Herrington ◽  
Scott F. Thrall ◽  
Leah M. Mann ◽  
Michael M. Tymko ◽  
Trevor A. Day
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Steady State ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Brain Blood Flow ◽  
Pressor Test ◽  
Regional Brain

Head-down-tilt bed rest alters forearm vasodilator and vasoconstrictor responses

1998 ◽  
Vol 84 (5) ◽  
pp. 1756-1762 ◽  
Author(s):  
J. Kevin Shoemaker ◽  
Cindy S. Hogeman ◽  
David H. Silber ◽  
Kristen Gray ◽  
Michael Herr ◽  
...  
Keyword(s):  
Blood Flow ◽  
Vascular Reactivity ◽  
Forearm Blood Flow ◽  
Circulatory Arrest ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Bed Rest ◽  
Venous Occlusion ◽  
Pressor Test ◽  
Sympathetic Discharge

To test the hypothesis that head-down-tilt bed rest (HDBR) for 14 days alters vascular reactivity to vasodilatory and vasoconstrictor stimuli, the reactive hyperemic forearm blood flow (RHBF, measured by venous occlusion plethysmography) and mean arterial pressure (MAP, measured by Finapres) responses after 10 min of circulatory arrest were measured in a control trial ( n = 20) and when sympathetic discharge was increased by a cold pressor test (RHBF + cold pressor test; n = 10). Vascular conductance (VC) was calculated (VC = RHBF/MAP). In the control trial, peak RHBF at 5 s after circulatory arrest (34.1 ± 2.5 vs. 48.9 ± 4.3 ml ⋅ 100 ml−1 ⋅ min−1) and VC (0.34 ± 0.02 vs. 0.53 ± 0.05 ml ⋅ 100 ml−1 ⋅ min−1 ⋅ mmHg−1) were reduced in the post- compared with the pre-HDBR tests ( P < 0.05). Total excess RHBF over 3 min was diminished in the post- compared with the pre-HDBR trial (84.8 vs. 117 ml/100 ml, P < 0.002). The ability of the cold pressor test to lower forearm blood flow was less in the post- than in the pre-HDBR test ( P < 0.05), despite similar increases in MAP. These data suggest that regulation of vascular dilation and the interaction between dilatory and constrictor influences were altered with bed rest.

Variability of the haemodynamic responses to laboratory tests employed in assessment of neural cardiovascular regulation in man

1985 ◽  
Vol 69 (5) ◽  
pp. 533-540 ◽  
Author(s):  
Gianfranco Parati ◽  
Guido Pomidossi ◽  
Agustin Ramirez ◽  
Bruno Cesana ◽  
Giuseppe Mancia
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Test Performance ◽  
Blood Pressure Response ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Cardiovascular Regulation ◽  
Pressor Test ◽  
Carotid Baroreceptor ◽  
Baroreceptor Stimulation

1. In man evaluation of neural cardiovascular regulation makes use of a variety of tests which address the excitatory and reflex inhibitory neural influences that control circulation. Because interpretation of these tests is largely based on the magnitude of the elicited haemodynamic responses, their reproducibility in any given subject is critical. 2. In 39 subjects with continuous blood pressure (intra-arterial catheter) and heart rate monitoring we measured (i) the blood pressure and heart rate rises during hand-grip and cold-pressor test, (ii) the heart rate changes occurring during baroreceptor stimulation and deactivation by injection of phenylephrine and trinitroglycerine, and (iii) the heart rate and blood pressure changes occurring with alteration in carotid baroreceptor activity by a neck chamber. Each test was carefully standardized and performed at 30 min intervals for a total of six times in each subject. 3. The results showed that the responses to any test were clearly different from one another and that this occurred in all subjects studied. For the group as a whole the average response variability (coefficient of variation) ranged from 10.2% for the blood pressure response to carotid baroreceptor stimulation to 44.2% for the heart rate response to cold-pressor test. The variability of the responses was not related to basal blood pressure or heart rate, nor to the temporal sequence of the test performance. 4. Thus tests employed for studying neural cardiovascular control in man produce responses whose reproducibility is limited. This phenomenon may make it more difficult to define the response magnitude typical of each subject, as well as its comparison in different conditions and diseases.

Blood Pressure and Vascular Reactivity to the Cold Pressor Test

JAMA ◽  
1963 ◽  
Vol 183 (10) ◽  
Author(s):  
Paul H. Barnett ◽  
Edgar A. Hines ◽  
Alexander Schirger ◽  
Robert P. Gage
Keyword(s):  
Blood Pressure ◽  
Vascular Reactivity ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Pressor Test
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