Haemodynamic effects of physiological concentrations of circulating noradrenaline in man

1988 ◽  
Vol 75 (5) ◽  
pp. 469-475 ◽  
Author(s):  
Peter C. Chang ◽  
Eugene Kriek ◽  
Jacques A. Van Der Krogt ◽  
Gerard-Jan Blauw ◽  
Peter Van Brummelen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Vascular Resistance ◽  
Forearm Blood Flow ◽  
Haemodynamic Effects ◽  
Plasma Noradrenaline ◽  
Arterial Blood ◽  
Forearm Vascular Resistance ◽  
Venous Plasma

1. To define the role of circulating noradrenaline in cardiovascular regulation, threshold concentrations for haemodynamic effects were determined in arterial and venous plasma of eight healthy volunteers. 2. Five doses of noradrenaline, 0–54 ng min−1 kg−1, were infused intravenously in random order and single-blind for 15 min per dose. Changes in intra-arterial blood pressure, heart rate, forearm blood flow and forearm vascular resistance were determined, and plasma noradrenaline was measured in arterial and venous blood samples. 3. Significant increases in systolic and diastolic blood pressure were found at arterial and venous plasma noradrenaline concentrations (means ±sem) of 3.00 ± 0.23 and 1.35 ±0.12 nmol/l, respectively. A significant decrease in heart rate was found at arterial and venous plasma noradrenaline concentrations of 8.99 ± 0.69 and 3.09 ± 0.60 nmol/l, respectively. The lower doses of noradrenaline tended to increase forearm blood flow and to decrease forearm vascular resistance, whereas the higher doses had no consistent effect on forearm haemodynamics. 4. During the noradrenaline infusions 73 ± 5% of the increase in arterial plasma noradrenaline concentration was extracted in the forearm. 5. The venous plasma noradrenaline threshold concentration was found to be much lower than previously reported. It is concluded that arterial and venous plasma noradrenaline concentrations which are readily encountered in physiological circumstances elicit haemodynamic effects.

Forearm and finger blood flow responses to passive body tilts

1979 ◽  
Vol 46 (2) ◽  
pp. 288-292 ◽  
Author(s):  
Y. A. Mengesha ◽  
G. H. Bell
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Pulse Rate ◽  
Forearm Blood Flow ◽  
Body Tilt ◽  
Finger Blood Flow ◽  
Arterial Blood ◽  
Forearm Vascular Resistance

Ten to fifteen healthy subjects, ages 18--30 yr, were used to assess the correlation of forearm blood flow with graded passive body tilts and vascular resistance and also to discern the relative effects of body tilts on finger blood flow. In the head-up tilts forearm blood flow and arterial blood pressure fell progressively, whereas forearm vascular resistance and pulse rate increased. In the head-down tilts the forearm blood flow and the arterial blood pressure increased, whereas the forearm vascular resistance and pulse rate decreased. These changes were found to be significantly correlated with the different tilt angles and with one another. In a preliminary study it was found that infrared heating of the carpometacarpal region produced finger vasodilatation similar to the forearm vasodilatation observed by Crockford and Hellon (6). However, unlike forearm blood flow, finger blood flow showed no appreciable response to either the head-up or head-down tilts. This indicates that the sympathetic tone and the volume of blood in the finger are not appreciably altered by this test procedure at least 1 min after the body tilt is assumed.

Effect of Chronic Smoking on Endothelium-Dependent Vascular Relaxation in Humans

1993 ◽  
Vol 85 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Marie-Cécile Jacobs ◽  
Jacques W. M. Lenders ◽  
Jan A. Kapma ◽  
Paul Smits ◽  
Theo Thien
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cigarette Smoking ◽  
Sodium Nitroprusside ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Forearm Blood Flow ◽  
Vascular Relaxation ◽  
Arterial Blood ◽  
Forearm Vascular Resistance

1. Cigarette smoking is one of the major risk factors for the development of atherosclerosis. It is not clear, however, whether chronic cigarette smoking impairs the normal physiological function of the endothelium before the development of morphological vascular lesions. To test this, we investigated endothelium-dependent vascular relaxation in young habitual smoking subjects. 2. In 11 non-smokers and 10 habitual smokers we measured the changes in bilateral forearm blood flow, arterial blood pressure and forearm vascular resistance (ratio between mean arterial blood pressure and forearm blood flow) during three interventions: postocclusive forearm hyperaemia, intrabrachial infusion of methacholine which causes vasodilatation by stimulating the release of endothelium-dependent relaxing factor, and intrabrachial infusion of sodium nitroprusside which causes vasodilatation independently from the endothelium by a direct effect on the vascular smooth muscle wall. 3. During infusion of the highest dose of methacholine, forearm vascular resistance decreased by 91.7 ± 1.4% in the smokers and by 89.9 ± 1.8% in the non-smokers. During infusion of sodium nitroprusside, forearm vascular resistance decreased by 80.0 ± 3.8% in the smokers as compared with 80.7 ± 6.1% in the non-smokers. There was no difference in basal forearm vascular resistance or in post-ischaemic reactive hyperaemia between smokers and non-smokers. Thus, vasodilatation induced by both methacholine and sodium nitroprusside was not significantly different between smokers and non-smokers. 4. We conclude that in young habitual cigarette smokers the endothelium-dependent vasodilatation in the forearm seems to be preserved, suggesting that habitual smoking does not result in permanent endothelial dysfunction in the human forearm.

Effect of hypovolemia on forearm vascular resistance control during exercise in the heat

1991 ◽  
Vol 71 (4) ◽  
pp. 1382-1386 ◽  
Author(s):  
T. S. Nishiyasu ◽  
X. G. Shi ◽  
G. W. Mack ◽  
E. R. Nadel
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Forearm Blood Flow ◽  
Cycle Ergometer ◽  
Dynamic Exercise ◽  
Arterial Blood ◽  
Ergometer Exercise ◽  
Forearm Vascular Resistance

To determine the influence of hypovolemia on the control of forearm vascular resistance (FVR) during dynamic exercise, we studied five physically active men during 60 min of supine cycle ergometer exercise bouts at 35 degrees C in control (normovolemic) and hypovolemic conditions. Hypovolemia was achieved by 3 days of diuretic administration and resulted in an average decrease in plasma volume of 15.9%. Relative to normovolemia, hypovolemia caused an attenuation of the progressive rise in forearm blood flow (P less than 0.05) and an increase in heart rate (P less than 0.05) during exercise. Because mean arterial blood pressure during hypovolemic exercise was well maintained, the attenuation of forearm blood flow was due entirely to a relative increase in FVR. At the onset of dynamic exercise, FVR was increased significantly in control and hypovolemic conditions by 13.2 and 27.1 units, respectively. The increase in FVR was significantly different between control and hypovolemic conditions as well. We attributed the increased vasoconstrictor bias during hypovolemia to cardiopulmonary baroreceptor unloading and/or an increased sensitivity to cardiopulmonary baroreceptor unloading. We concluded that reduced blood flow to the periphery during exercise in the hypovolemic condition was caused entirely by an increase in vascular resistance, thereby preserving arterial blood pressure and adequate perfusion to the organs requiring increased flow.

Sympathetic vascular transduction is augmented in young normotensive blacks

2002 ◽  
Vol 92 (2) ◽  
pp. 651-656 ◽  
Author(s):  
Chester A. Ray ◽  
Kevin D. Monahan
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Forearm Blood Flow ◽  
Lower Body Negative Pressure ◽  
Muscle Sympathetic Nerve Activity ◽  
Arterial Blood ◽  
Blacks And Whites

The purpose of the present study was to determine sympathetic vascular transduction in young normotensive black and white adults. We hypothesized that blacks would demonstrate augmented transduction of muscle sympathetic nerve activity (MSNA) into vascular resistance. To test this hypothesis, MSNA, forearm blood flow, heart rate, and arterial blood pressure were measured during lower body negative pressure (LBNP). At rest, no differences existed in arterial blood pressure, heart rate, forearm blood flow, and forearm vascular resistance (FVR). Likewise, LBNP elicited comparable responses of these variables for blacks and whites. Baseline MSNA did not differ between blacks and whites, but whites demonstrated greater increases during LBNP (28 ± 7 vs. 55 ± 18%, 81 ± 21 vs. 137 ± 42%, 174 ± 81 vs. 556 ± 98% for −5, −15, and −40 mmHg LBNP, respectively; P < 0.001). Consistent with smaller increases in MSNA but similar FVR responses during LBNP, blacks demonstrated greater sympathetic vascular transduction (%FVR/%MSNA) than whites (0.95 ± 0.07 vs. 0.82 ± 0.07 U; 0.82 ± 0.11 vs. 0.64 ± 0.09 U; 0.95 ± 0.37 vs. 0.35 ± 0.09 U; P < 0.01). In summary, young whites demonstrate greater increases in MSNA during baroreceptor unloading than age-matched normotensive blacks. However, more importantly, for a given increase in MSNA, blacks demonstrate greater forearm vasoconstriction than whites. This finding may contribute to augmented blood pressure reactivity in blacks.

Patterned cardiovascular responses to sleep and nonrespiratory arousals in a porcine model

1998 ◽  
Vol 85 (4) ◽  
pp. 1285-1291 ◽  
Author(s):  
Sandrine H. Launois ◽  
Joseph H. Abraham ◽  
J. Woodrow Weiss ◽  
Debra A. Kirby
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Eye Movement ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Mean Arterial Blood Pressure ◽  
Rapid Eye Movement ◽  
Rapid Eye Movement Sleep ◽  
Arterial Blood

Patients with obstructive sleep apnea experience marked cardiovascular changes with apnea termination. Based on this observation, we hypothesized that sudden sleep disruption is accompanied by a specific, patterned hemodynamic response, similar to the cardiovascular defense reaction. To test this hypothesis, we recorded mean arterial blood pressure, heart rate, iliac blood flow and vascular resistance, and renal blood flow and vascular resistance in five pigs instrumented with chronic sleep electrodes. Cardiovascular parameters were recorded during quiet wakefulness, during non-rapid-eye-movement and rapid-eye-movement sleep, and during spontaneous and induced arousals. Iliac vasodilation (iliac vascular resistance decreased by −29.6 ± 4.1% of baseline) associated with renal vasoconstriction (renal vascular resistance increased by 10.3 ± 4.0%), tachycardia (heart rate increase: +23.8 ± 3.1%), and minimal changes in mean arterial blood pressure were the most common pattern of arousal response, but other hemodynamic patterns were observed. Similar findings were obtained in rapid-eye-movement sleep and for acoustic and tactile arousals. In conclusion, spontaneous and induced arousals from sleep may be associated with simultaneous visceral vasoconstriction and hindlimb vasodilation, but the response is variable.

Effect of intravenous infusion of adrenaline on the cardiovascular responses to distal body subatmospheric pressure in man

1988 ◽  
Vol 75 (4) ◽  
pp. 389-394 ◽  
Author(s):  
I. W. Fellows ◽  
I. A. MacDonald ◽  
T. Bennett ◽  
D. P. O'Donoghue
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Forearm Blood Flow ◽  
Cardiovascular Responses ◽  
Saline Infusion ◽  
Subatmospheric Pressure ◽  
Arterial Blood ◽  
Adrenaline Infusion

1. On two separate occasions, at least 1 week apart, seven young healthy male subjects received intravenous infusions of either adrenaline [0.27 nmol (50 ng) min−1 kg−1] or saline (154 mmol/l NaCl), plus ascorbic acid (5.68 mmol/l), over 30 min. 2. On each occasion, the subjects were exposed to distal body subatmospheric pressure (DBSP), 0 to 50 mmHg (0 to 6.65 kPa) in 10 mmHg (1.33 kPa) steps, before infusion, during the final 15 min of the infusion, and at 15 min and 30 min after the cessation of the infusion. 3. Venous adrenaline concentrations of 2.85 ±0.22 nmol/l were achieved during the adrenaline infusion, compared with 0.49 ± 0.07 nmol/l during the saline infusion (P < 0.001). At 15 min and at 30 min after cessation of the adrenaline infusion, venous adrenaline concentrations had fallen to levels similar to those achieved after the cessation of the saline infusion. 4. Heart rate rose significantly from 58 ±4 beats/min to 67 ±4 beats/min during the adrenaline infusion (P < 0.05), but there was no further significant change in response to 50 mmHg (6.65 kPa) DBSP. At 30 min after the cessation of the adrenaline infusion, heart rate rose from 60 ± 4 beats/min to 78 ± 7 beats/min in response to 50 mmHg DBSP. This increase was significantly greater than that observed before the adrenaline infusion [58 ± 4 beats/min to 69 ±7 beats/min during 50 mmHg (6.65 kPa) DBSP; P < 0.01]. 5. During the infusion of adrenaline, systolic arterial blood pressure rose and diastolic arterial blood pressure fell, but the blood pressure responses to DBSP were unaffected. 6. Forearm blood flow increased significantly during adrenaline infusion but there was no significant difference in the fall in forearm blood flow during DBSP compared with the values before infusion. At 15 min after the cessation of the adrenaline infusion, forearm vascular resistance rose proportionately more in response to DBSP than it had before the adrenaline infusion (P < 0.05). 7. These results are consistent with adrenaline-mediated facilitation of sympathetic neuronal release of noradrenaline in the heart and in the forearm vascular bed.

Age-independent forearm vasodilatation by acetylcholine and adenosine 5′-triphosphate in humans

1990 ◽  
Vol 78 (1) ◽  
pp. 89-93 ◽  
Author(s):  
Tsutomu Imaizumi ◽  
Akira Takeshita ◽  
Satoshi Suzuki ◽  
Megumu Yoshida ◽  
Shinichi Ando ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Sodium Nitroprusside ◽  
Vascular Resistance ◽  
Brachial Artery ◽  
Forearm Blood Flow ◽  
Resistance Arteries ◽  
Dose Dependent ◽  
Forearm Vascular Resistance ◽  
Age Independent

1. Forearm vasodilator responses to acetylcholine, ATP and sodium nitroprusside were examined in healthy young (20 ± 1 years, n = 9), middle-aged (46 ± 2 years, n = 6) and old (57 ± 1 years, n = 6) subjects. 2. A brachial artery was cannulated with a 20-gauge cannula through which drugs at graded doses were locally infused for 2 min at each dose. During drug infusions, forearm blood flow was continuously measured at 15 s intervals using a plethysmograph. Forearm vascular resistance was calculated from forearm blood flow and mean blood pressure obtained in the opposite arm. Basal forearm blood flow and forearm vascular resistance did not differ between the three groups. 3. Acetylcholine and ATP were used to examine endothelium-dependent vasodilatation, and sodium nitroprusside was used to examine endothelium-independent vasodilatation. All three drugs caused dose-dependent increases in forearm blood flow (P < 0.01) and decreases in forearm vascular resistance (P < 0.01). The increases in forearm blood flow or decreases in forearm vascular resistance in response to infusions of the three drugs did not differ between the three groups. 4. These results suggest that endothelium-dependent and endothelium-independent vasodilatation in forearm resistance arteries do not alter with ageing in humans.

Sequential Changes in Plasma Noradrenaline during Bicycle Exercise

1980 ◽  
Vol 58 (1) ◽  
pp. 37-43 ◽  
Author(s):  
R. D. S. Watson ◽  
C. A. Hamilton ◽  
D. H. Jones ◽  
J. L. Reid ◽  
T. J. Stallard ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Supine Position ◽  
Sympathetic Activity ◽  
Plasma Noradrenaline ◽  
Bicycle Exercise ◽  
Hypertensive Patients ◽  
Arterial Blood ◽  
Exercise Blood Pressure ◽  
Venous Plasma

1. Forearm venous plasma noradrenaline, heart rate and intra-arterial blood pressure were measured sequentially during and after upright bicycle exercise in five normotensive and six hypertensive patients. 2. Plasma noradrenaline increased significantly between 4 and 8 min during exercise. 3. On stopping exercise blood pressure and heart rate decreased rapidly whilst plasma noradrenaline increased in each subject to reach a maximum at a median time of 108 s after exercise. 4. Plasma noradrenaline decreased in five of six normotensive patients between the end of exercise and 2 min after exercise performed in the supine position. 5. Evidence in favour of a reflex increase in sympathetic activity after upright exercise is discussed.

Baroreflex function in endurance- and static exercise-trained men

1988 ◽  
Vol 64 (2) ◽  
pp. 585-591 ◽  
Author(s):  
M. L. Smith ◽  
H. M. Graitzer ◽  
D. L. Hudson ◽  
P. B. Raven
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Vascular Resistance ◽  
Forearm Blood Flow ◽  
Lower Body Negative Pressure ◽  
Correlation Coefficients ◽  
Cardiovascular Responses ◽  
Cross Sectional ◽  
Baroreflex Function

The effect of exercise training mode on reflex cardiovascular control was studied in a cross-sectional design. We examined the cardiovascular responses to progressive incremental phenylephrine (PE) infusion to maximal rates of 120 micrograms/min and the delta heart rate/delta blood pressure responses to lower body negative pressure (LBNP) to -50 Torr in 30 men who were either endurance exercise trained (ET), untrained (UT), or weight trained (WT). During PE infusion, measures of blood pressures, forearm blood flow, heart rate and cardiac output, and calculations of forearm vascular resistance, stroke volume, and peripheral vascular resistance were made at each infusion rate when steady-state blood pressure was attained. No significant differences (P less than 0.05) in forearm blood flow or resistance were observed between the groups at any dose of PE, suggesting that the vasoconstrictor response was similar among the groups. Regression analyses of heart rate against mean blood pressure during the PE infusion were performed to evaluate baroreflex function. A linear model was used and correlation coefficients ranging from 0.82 to 0.96 were obtained (P less than 0.05). The slope of the line of best fit for the ET subjects (-0.57) was significantly less (P less than 0.05) than the slopes obtained for either the UT (-0.91) or WT (-0.88) subjects. In addition, the delta heart rate/delta blood pressure measurements obtained during LBNP reflected a similarly significant attenuation of reflex chronotropic control in the ET subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute haemodynamic effects of lipolysis-induced increase of free fatty acids in healthy men

2002 ◽  
Vol 102 (5) ◽  
pp. 495-500 ◽  
Author(s):  
Mark T. KEARNEY ◽  
Philip J. CHOWIENCZYK ◽  
Sally E. BRETT ◽  
Angela SUTCLIFFE ◽  
James M. RITTER ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Fatty Acids ◽  
Blood Flow ◽  
Free Fatty Acids ◽  
Arterial Blood Pressure ◽  
Lipid Emulsion ◽  
Forearm Blood Flow ◽  
Haemodynamic Effects ◽  
Healthy Men ◽  
Arterial Blood

Circulating free fatty acids (FFA) are elevated in subjects with insulin resistance and Type II diabetes, and increase during myocardial ischaemia, but their haemodynamic effects are incompletely understood. During an investigation of the effects of FFA on endothelial function, we administered lipid emulsion (150mgċmin-1 of soybean oil) with heparin (0.2 unitċkg-1ċmin-1) intravenously to eight healthy men for 2h. This increased circulating FFA to 3.1±0.5mmol/l. Forearm blood flow was measured by venous occlusion plethysmography during brachial artery infusions of saline, acetylcholine and nitroprusside before, and at 1 and 2h. Lipid/heparin infusion had no significant effect on vasodilation to nitroprusside but progressively increased responses to acetylcholine (from 6.3±2.0 during 30μgċmin-1 before-lipid infusion to 7.9±1.3 at 1h and 12.2±1.1mlċmin-1ċ100ml-1 at 2h, P < 0.001). Basal flow increased from 2.7±0.7 to 4.7±0.8mlċmin-1ċ100ml-1 from 0 to 2h. We performed a second study to clarify this effect on basal blood flow. Healthy men (n = 8) received, on separate occasions, 4h intravenous infusions of lipid emulsion with heparin and, as a control, saline with heparin. Lipid with heparin increased mean arterial blood pressure (maximum increment 8.2±2.7mmHg, P < 0.01 compared with saline/heparin control) and forearm blood flow (from 1.7±0.2 to 2.9±0.3mlċmin-1ċ100ml-1, P < 0.01) without a significant effect on heart rate, and reduced calculated forearm vascular resistance (from 49.1±5.4 to 31.3±3.9 arbitrary units, P < 0.01). In conclusion, acute elevation of FFA in healthy men increases arterial blood pressure and reduces vascular resistance. These haemodynamic changes could be clinically relevant.

Sign in / Sign up

Export Citation Format

Share Document