REDUCED PLASMA RENIN ACTIVITY IN ELDERLY SUBJECTS IN RESPONSE TO VASOVAGAL HYPOTENSION AND HEAD-UP TILT

1987 ◽  
Vol 16 (3) ◽  
pp. 171-177 ◽  
Author(s):  
ROSE ANNE KENNY ◽  
CALUM C. LYON ◽  
JOHN BAYLISS ◽  
STAFFORD L LIGHTMAN ◽  
RICHARD SUTTON
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Renin Activity ◽  
Elderly Subjects ◽  
Head Up Tilt

Reduced Plasma Renin Activity in Elderly Subjects in Response to Vasovagal Hypotension and Head Up Tilt

1986 ◽  
Vol 70 (s13) ◽  
pp. 25P-25P
Author(s):  
R A Kenny ◽  
C Lyon ◽  
J Bayliss ◽  
S Dixon ◽  
S Lightman ◽  
...  
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Renin Activity ◽  
Elderly Subjects ◽  
Head Up Tilt

CARDIOVASCULAR HAEMODYNAMICS AND THE RESPONSE OF VASOPRESSIN, ALDOSTERONE, PLASMA RENIN ACTIVITY AND PLASMA CATECHOLAMINES TO HEAD-UP TILT IN YOUNG AND OLD HEALTHY SUBJECTS

1986 ◽  
Vol 15 (1) ◽  
pp. 17-28 ◽  
Author(s):  
ENRIQUE VARGAS ◽  
MICHAEL LYE ◽  
E. BRIAN FARAGHER ◽  
CHRISTOPHER GODDARD ◽  
BILL MOSER ◽  
...  
Keyword(s):  
Plasma Renin Activity ◽  
Healthy Subjects ◽  
Plasma Catecholamines ◽  
Plasma Renin ◽  
Renin Activity ◽  
Head Up Tilt

Plasma Catecholamines, Plasma Renin Activity and Plasma Aldosterone in Tetraplegic Man, Horizontal and Tilted

1975 ◽  
Vol 49 (4) ◽  
pp. 291-299 ◽  
Author(s):  
C. J. Mathias ◽  
N. J. Christensen ◽  
J. L. Corbett ◽  
H. L. Frankel ◽  
T. J. Goodwins ◽  
...  
Keyword(s):  
Plasma Renin Activity ◽  
Cervical Spinal Cord ◽  
Plasma Catecholamines ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Normal Male ◽  
Head Up Tilt ◽  
The Brain

1. Plasma catecholamines, plasma renin activity, plasma aldosterone and haematocrit were measured in four subjects with physiologically complete cervical spinal cord transections, before, during and after head-up tilt to 45° for 30 min. Plasma catecholamines were measured in five normal male volunteers in the supine position and after head-up tilt to 45° for 10 min. 2. After 10 min of head-up tilt, the plasma noradrenaline rose 14% in the tetraplegic patients and 115% in the control subjects. These findings indicate a failure of sympathetic activity in response to head-up tilt in the tetraplegic patients, probably caused by interruption of pathways by which the brain normally controls sympathetic outflow. 3. In the tetraplegic patients the resting plasma renin activities were above normal, and rose more quickly and greater on head-up tilt than in published studies of normal subjects. It is likely that the renal baroreceptors are important in the control of renin release. 4. In the tetraplegic patients, there was a late rise in plasma aldosterone which was probably due to the elevation in plasma renin activity.

Effects of aging on human plasma renin: simultaneous multiple assays of enzyme activity and immunoactivity of plasma renin

1989 ◽  
Vol 120 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Jitsuo Higaki ◽  
Ryuichi Morishita ◽  
Toshio Ogihara ◽  
Masaru Nishiura
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Normal Subjects ◽  
The Elderly ◽  
Renin Activity ◽  
Elderly Subjects ◽  
Plasma Renin Concentration ◽  
Active Renin ◽  
Effects Of Aging ◽  
Renin Content

Abstract. The effects of aging on plasma renin in normotensive volunteers were evaluated by conventional indirect RIA of angiotensin I and a newly developed direct RIA. Plasma renin activity and the plasma concentration of active renin measured by radiometric assay with monoclonal antibody were significantly lower in 14 subjects over 60 years than in 15 subjects under 60 years (plasma renin activity: 0.5 ± 0.1 vs 1.7 ± 0.4 nmol · 1−1 · h−1, P< 0.01; plasma active renin: 0.50 ± 0.05 vs 0.87 ± 0.13 pmol/l, P< 0.01, means ± sem), wheres neither the total renin activity nor the total plasma renin concentration measured by the newly developed immunometric assay were different in the two groups. In another study, the plasma renin concentration, total renin concentration and immunoreactive total renin concentration measured by direct RIA with polyclonal antibody were determined in 17 young (<60 years) and 12 elderly (≧60 years) subjects. Plasma renin concentration was significantly lower in the elderly subjects (1.7 ± 0.2 nmol · 1−1 · h−1) than in young subjects (3.4 ± 0.7 nmol · 1−1 · h−1, P< 0.05), but the total renin concentration and immunoreactive total renin concentrations in the two groups were not significantly different. These results indicate that the total renin content of the plasma does not change, whereas the active renin content decreases with age in normal subjects, and suggest that activation of prorenin to active renin may be impaired in elderly subjects.

Anti-Hypertensive Effect of Acebutolol: Its Relation to Sympathetic Nervous System Responsiveness and to Plasma Renin and Dopamine-β-Hydroxylase Activities

1976 ◽  
Vol 51 (s3) ◽  
pp. 477s-480s
Author(s):  
A. Fournier ◽  
J. M. Hardin ◽  
J. M. Alexandre ◽  
M. Lombaert ◽  
G. Ronco ◽  
...  
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Renin Activity ◽  
Daily Dose ◽  
Head Up Tilt ◽  
The Common ◽  
System Responsiveness ◽  
Sympathetic Nervous

1. Acebutolol, a β1-receptor blocker, has, at a daily dose of 800 mg, a mild but significant anti-hypertensive effect in moderate sustained essential hypertension with normal or low plasma renin activity. 2. Prediction of its anti-hypertensive effect is better based on the evaluation of the sympathetic nervous system responsiveness to head-up tilt than on the evaluation of plasma renin activity or dopamine-β-hydroxylase. 3. The anti-hypertensive effect of acebutolol is better explained on the basis of inhibition of the sympathetic nervous system activity than on the basis of suppression of plasma renin activity. 4. A positive correlation between plasma renin activity and dopamine-β-hydroxylase in patients on diuretics suggests the common dependence of these two variables on sympathetic overactivity.

Increased Central Blood Volume: A Possible Pathophysiological Factor in Mild Low-Renin Essential Hypertension

1976 ◽  
Vol 51 (s3) ◽  
pp. 207s-210s ◽  
Author(s):  
S. Julius ◽  
M. Esler
Keyword(s):  
Essential Hypertension ◽  
Plasma Renin Activity ◽  
Blood Volume ◽  
Plasma Renin ◽  
Renin Activity ◽  
Total Blood Volume ◽  
Central Blood Volume ◽  
Total Blood ◽  
Low Renin Hypertension ◽  
Head Up Tilt

1. Patients with mild low-renin hypertension characteristically have increased central blood volume. The total blood volume is normal; the larger central blood volume reflects a shift of the blood from peripheral to central (cardiopulmonary) segments of the capacity system. 2. A relationship between central blood volume and plasma renin activity is demonstrable during tilting in normal and hypertensive subjects. In thirteen individuals there was a strong correlation between the decrease of the central blood volume and the increase in plasma renin activity in response to 12 min of 35° head-up tilt. 3. We propose that the elevated central blood volume causes greater stretch of cardiopulmonary mechanoreceptors and this in turn depresses renin release in mild low-renin hypertension.

Suppression of the Renin—Aldosterone System in Mild Essential Hypertension

1976 ◽  
Vol 50 (4) ◽  
pp. 269-276
Author(s):  
A. M. Khokhar ◽  
J. D. H. Slater ◽  
T. P. Jowett ◽  
N. N. Payne
Keyword(s):  
Essential Hypertension ◽  
Plasma Renin Activity ◽  
Extracellular Fluid ◽  
Young Men ◽  
Plasma Renin ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Renin Activity ◽  
Low Renin Hypertension ◽  
Head Up Tilt

1. Suppression of the renin—aldosterone system by expansion of the extracellular fluid volume with extra sodium and mineralocorticoid for 6 days was studied in nine young men with very mild essential hypertension and in ten normotensive young men. 2. Plasma renin activity, measured both supine and after 45° head-up tilt, and the renal excretion of aldosterone 18-glucuronide were similar in both groups. However, after expansion of the extracellular fluid volume, hypertensive patients showed much less suppression of both variables. 3. This difference persisted despite matching for an equivalent degree of expansion of the extracellular fluid volume as indexed by the change in body weight. 4. Administration of extra sodium and mineralocorticoid produced a greater proportional fall of renal aldosterone excretion than of plasma renin activity in both groups and this dissociation was significantly more marked in the hypertensive group. 5. We suggest that (i) a relative autonomy of the renin—aldosterone system may be relevant to the pathogenesis and/or perpetuation of essential hypertension and (ii) that the syndrome of low-renin hypertension is unlikely to be associated with ‘mineralocorticoid’ excess.

Renin Release during Head-up Tilt Occurs Independently of Sympathetic Nervous Activity in Tetraplegic Man

1980 ◽  
Vol 59 (4) ◽  
pp. 251-256 ◽  
Author(s):  
C. J. Mathias ◽  
N. J. Christensen ◽  
H. L. Frankel ◽  
W. S. Peart
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Nervous Activity ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Renin Activity ◽  
Plasma Noradrenaline ◽  
Sympathetic Nervous Activity ◽  
Head Up Tilt ◽  
Sympathetic Nervous

1. The role of the sympathetic nervous system in the release of renin during head-up tilt has been studied in five normal subjects and in four tetraplegic patients with cervical spinal-cord transection above the sympathetic outflow. Blood pressure, heart rate and concentrations of plasma noradrenaline, plasma adrenaline and plasma renin activity were measured during head-up tilt to 45° before and after acute β-adrenoreceptor blockade with intravenous propranolol. 2. In the normal subjects there were minimal changes in blood pressure during head-up tilt and there was a rise in both plasma noradrenaline concentration and plasma renin activity. After propranolol values of plasma renin activity at rest fell with little change occurring during head-up tilt. 3. In the tetraplegic patients there was a substantial fall in blood pressure during head-up tilt. Concentrations of plasma noradrenaline and adrenaline did not change but there was a marked increase in plasma renin activity. Values of plasma renin activity both at rest and during head-up tilt were unaffected by propranolol. 4. We conclude that in tetraplegic patients renin release during head-up tilt may occur independently of sympathetic nervous activity and is probably largely dependent on activation of renal vascular receptors.

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