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.

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.

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.

L-propionylcarnitine increases postischemic blood flow but does not affect recovery of energy charge

1991 ◽  
Vol 261 (1) ◽  
pp. H172-H180 ◽  
Author(s):  
L. M. Sassen ◽  
K. Bezstarosti ◽  
W. J. Van der Giessen ◽  
J. M. Lamers ◽  
P. D. Verdouw
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Systemic Vascular Resistance ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Contractile Function ◽  
Energy Charge ◽  
Left Ventricular ◽  
Arterial Blood

Effects of pretreatment with L-propionylcarnitine (50 mg/kg, n = 9) or saline (n = 10) were studied in open-chest anesthetized pigs, in which ischemia was induced by decreasing left anterior descending coronary artery blood flow to 20% of baseline. After 60 min of ischemia, myocardium was reperfused for 2 h. In both groups, flow reduction abolished contractile function of the affected myocardium and caused similar decreases in ATP (by 55%) and energy charge [(ATP + 0.5ADP)/(ATP + ADP + AMP); decrease from 0.91 to 0.60], mean arterial blood pressure (by 10-24%), the maximum rate of rise in left ventricular pressure (by 26-32%), and cardiac output (by 20-30%). During reperfusion, “no-reflow” was attenuated by L-propionylcarnitine, because myocardial blood flow returned to 61 and 82% of baseline in the saline- and L-propionylcarnitine-treated animals, respectively. Cardiac output of the saline-treated animals further decreased (to 52% of baseline), and systemic vascular resistance increased from 46 +/- 3 to 61 +/- 9 mmHg.min.l-1, thereby maintaining arterial blood pressure. In L-propionylcarnitine-treated pigs, cardiac output remained at 75% of baseline, and systemic vascular resistance decreased from 42 +/- 3 to 38 +/- 4 mmHg.min.l-1. In both groups, energy charge but not the ATP level of the ischemic-reperfused myocardium tended to recover, whereas the creatine phosphate level showed significantly more recovery in saline-treated animals. We conclude that L-propionylcarnitine partially preserved vascular patency in ischemic-reperfused porcine myocardium but had no immediate effect on “myocardial stunning.” Potential markers for long-term recovery were not affected by L-propionylcarnitine.

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.

Rapid effects of parathyroid hormone(1–34) and prostaglandin E2 on bone blood flow and strontium clearance in the rat in vivo

1991 ◽  
Vol 131 (3) ◽  
pp. 359-365 ◽  
Author(s):  
E. Cochrane ◽  
I. D. McCarthy
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Parathyroid Hormone ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Prostaglandin E ◽  
Bone Blood Flow ◽  
Vascular Effects ◽  
Arterial Blood ◽  
Mineral Ions

ABSTRACT The vascular effects of noradrenaline, ATP, parathyroid hormone (PTH) and prostaglandin E2 (PGE2) were investigated in the rat. Additionally, the exchange of mineral ions between bone and blood was assessed by measuring strontium clearance, with the aim of investigating whether the vascular effects of these agents altered uptake of mineral ions or if this exchange could be changed independently of blood flow. Radioactive microspheres and 85Sr were used to establish bone blood flow and mineral clearance. Measurements of bone blood flow and arterial pressure were made in each animal and used to calculate vascular resistance. A measurement of 85Sr clearance was also obtained. Arterial blood pressure was significantly affected by noradrenaline (P ≤ 0·003) and ATP (P ≤ 0·015). Additionally, noradrenaline significantly (P ≤ 0·03) reduced bone blood flow. This decrease was related to a significant increase in vascular resistance. Arterial blood pressure and bone blood flow were significantly reduced by both bovine PTH(1–34) (P ≤ 0·001, P ≤ 0·02) and PGE2 (P ≤ 0·005, P ≤ 0·001). Vascular resistance to bone was increased by both agents but this was only statistically significant in the case of PGE2 (P ≤ 0·01). A significant (P ≤ 0·001) reduction in strontium was also produced by PGE2. In each group the relationship between bone blood flow and strontium clearance was then analysed. Only the PGE2-treated group had a slope of the regression which was statistically different from both the control animals and the other drug-treated groups. Treatment with PGE2 therefore resulted in a dose-related decrease in 85Sr clearance which was not related to the reduction in bone blood flow. Journal of Endocrinology (1991) 131, 359–365

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.

Renal Vascular Responses to Dopamine: Haemodynamic and Angiographic Observations in Normal Man

1973 ◽  
Vol 45 (6) ◽  
pp. 733-742 ◽  
Author(s):  
N. K. Hollenberg ◽  
D. F. Adams ◽  
P. Mendell ◽  
H. L. Abrams ◽  
J. P. Merrill
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Cardiovascular Effects ◽  
Normal Subjects ◽  
Vascular Effects ◽  
Arterial Blood ◽  
Normal Man ◽  
Renal Vascular

1. The renal vascular response to intravenously administered dopamine was assessed in normal man by selective renal arteriography and xenon washout. Infusion of 3 μg min−1 kg−1 induced renal vasodilatation with an increase in the cortical component of blood flow. Arterial blood pressure was not influenced and a systemic effect was not demonstrable. Lower doses did not induce a renal response. Increasing dosage raised arterial blood pressure and induced subjective symptoms, but did not result in a further increase in renal blood flow. 2. Renal vascular resistance increased with increasing age in the normal subjects. A significant inverse relationship was found between the initial vascular resistance and the renal vasodilator response to dopamine. It thus appears that the vascular effects of increasing age (nephrosclerosis) may limit the dilator response to dopamine. 3. It is concluded that dopamine is an effective renal cortical vasodilator when administered intravenously at doses which are free from other systemic cardiovascular effects. The dose-response relationship must be considered in attempts at reversal of conditions characterized by renal vasoconstriction.

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