The Effects of Propranolol on Spontaneous and Experimental Hypertension in the Rat

1976 ◽  
Vol 51 (s3) ◽  
pp. 447s-450s
Author(s):  
A. C. Pessina ◽  
A. Corgnati ◽  
P. Palatini ◽  
C. Oneglia ◽  
C. Dal Palù
Keyword(s):  
Heart Rate ◽  
Plasma Renin Activity ◽  
Plasma Volume ◽  
Venous Pressure ◽  
Plasma Renin ◽  
Hypotensive Effect ◽  
Renin Activity ◽  
Experimental Hypertension ◽  
Volume Distribution ◽  
Haemodynamic Changes

1. The hypotensive effect of propranolol and its correlation with the changes in heart rate, plasma volume and plasma renin activity produced by this drug were studied in normotensive rats and in rats with spontaneous, renovascular and deoxycorticosterone-induced hypertension. 2. No correlation was found between the fall in arterial pressure and the reduction in heart rate and plasma volume. On the contrary, a direct correlation was found between the hypotensive response and plasma renin activity: rats with high renin showed the maximum response, those with low renin no response. 3. Studies on blood volume distribution in different organs and the direct measurement of blood flow in the splanchnic bed demonstrated a significant correlation between the effect of propranolol on capillary permeability and the haemodynamic changes which it causes, namely a significant increase in portal venous pressure.

Effect of Increasing Doses of Labetalol on Blood Pressure, Plasma Renin Activity and Aldosterone in Hypertensive Patients

1979 ◽  
Vol 57 (s5) ◽  
pp. 401s-404s ◽  
Author(s):  
A. Salvetti ◽  
R. Pedrinelli ◽  
P. Sassano ◽  
F. Arzilli
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Urinary Sodium Excretion ◽  
Hypotensive Effect ◽  
Inhibitory Effect ◽  
Renin Activity ◽  
Dose Dependent Fashion ◽  
Dose Dependent

1. Four different doses of labetalol (150, 300, 600 and 900 mg/day) were given for 1 week to each of four groups of patients with essential hypertension (six patients for each group). 2. Labetalol decreased mean blood pressure and heart rate to the same extent on the first and the seventh days of treatment. Only standing blood pressure showed a dose-dependent decrement, and heart rate showed a dose-dependent inhibition both in the supine and upright position. 3. Labetalol exerted a net inhibitory effect on plasma renin activity, which was related to basal renin values and was already maximal at the lowest doses. This effect was well maintained in the supine position, although during standing it tended to be less evident with increasing doses. 4. Urinary aldosterone was decreased in a dose-dependent fashion and its changes were largely independent of plasma renin activity. 5. Neither basal values nor changes of renin and aldosterone were related to the hypotensive effect of labetalol. 6. During labetalol treatment urinary sodium excretion fell for 2–3 days and then returned to basal values. The retentive effect of labetalol on sodium was directly related to the decrease of blood pressure, and the successive sodium escape might be explained either by the observed increase of plasma volume (indirectly measured by packed cell volume) or by aldosterone inhibition.

scholarly journals Effect of standing on neurohumoral responses and plasma volume in healthy subjects

1998 ◽  
Vol 84 (3) ◽  
pp. 914-921 ◽  
Author(s):  
Giris Jacob ◽  
Andrew C. Ertl ◽  
John R. Shannon ◽  
Raffaello Furlan ◽  
Rose Marie Robertson ◽  
...  
Keyword(s):  
Heart Rate ◽  
Plasma Renin Activity ◽  
Plasma Volume ◽  
Healthy Subjects ◽  
Plasma Renin ◽  
Urine Osmolality ◽  
Normal Subjects ◽  
Renin Activity ◽  
Blue Dye ◽  
Upright Posture

Upright posture leads to rapid pooling of blood in the lower extremities and shifts plasma fluid into surrounding tissues. This results in a decrease in plasma volume (PV) and in hemoconcentration. There has been no integrative evaluation of concomitant neurohumoral and PV shifts with upright posture in normal subjects. We studied 10 healthy subjects after 3 days of stable Na+ and K+ intake. PV was assessed by the Evans blue dye method and by changes in hematocrit. Norepinephrine (NE), NE spillover, epinephrine (Epi), vasopressin, plasma renin activity, aldosterone, osmolarity, and kidney response expressed by urine osmolality and by Na+ and K+ excretion of the subjects in the supine and standing postures were all measured. We found that PV fell by 13% (375 ± 35 ml plasma) over ∼14 min, after which time it remained relatively stable. There was a concomitant decrease in systolic blood pressure and an increase in heart rate that peaked at the time of maximal decrease in PV. Plasma Epi and NE increased rapidly to this point. Epi approached baseline by 20 min of standing. NE spillover increased 80% and clearance decreased 30% with 30 min of standing. The increase in plasma renin activity correlated with an increase in aldosterone. Vasopressin increased progressively, but there was no change in plasma osmolarity. The kidney response showed a significant decrease in Na+ and an increase in K+ excretion with upright posture. We conclude that a cascade of neurohumoral events occurs with upright posture, some of which particularly coincide with the decrease in PV. Plasma Epi levels may contribute to the increment in heart rate with maintained upright posture.

Anti-Hypertensive Adrenergic-Blocking Agents: Effects on Sodium Balance, the Renin-Angiotensin System and Haemodynamics

1974 ◽  
Vol 48 (s2) ◽  
pp. 93s-95s ◽  
Author(s):  
M. E. Safar ◽  
Y. A. Weiss ◽  
P. L. Corvol ◽  
J. E. Menard ◽  
G. M. London ◽  
...  
Keyword(s):  
Heart Rate ◽  
Plasma Renin Activity ◽  
Plasma Volume ◽  
Plasma Renin ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Sodium Balance ◽  
Blocking Agents ◽  
Adrenergic Blocking ◽  
Adrenergic Blocking Agents

1. The changes in plasma volume, haemodynamic variables, plasma renin activity and plasma aldosterone were studied in forty-one hypertensive patients after administration of adrenergic-blocking agents. Four drugs were used: alpha-methyldopa (fourteen patients), guanethidine (ten patients), clonidine (nine patients) and reserpine (eight patients). Drugs were administered orally during 7 days' hospitalization on a normal sodium diet (110 mmol/day). 2. The four drugs had similar effects: a significant decrease in blood pressure, a significant increase in plasma volume and no change in stroke volume. 3. With alpha-methyldopa and guanethidine, heart rate, plasma renin activity and plasma aldosterone were unchanged. 4. With reserpine and clonidine, heart rate and plasma renin activity were significantly decreased, whereas plasma aldosterone did not change significantly. 5. This study suggests that the decrease in plasma renin activity was related to the lowering of the heart rate rather than to sodium retention and that adrenergic-blocking agents can impair the normal relationship between stroke index and plasma volume, between plasma volume and plasma renin activity, and between plasma renin activity and plasma aldosterone.

Differential maturation of beta-adrenoceptor-mediated responses in the lamb fetus

1988 ◽  
Vol 255 (5) ◽  
pp. R794-R798 ◽  
Author(s):  
N. M. Rawashdeh ◽  
J. C. Rose ◽  
N. D. Ray
Keyword(s):  
Heart Rate ◽  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Renin Secretion ◽  
Renin Activity ◽  
Functional Maturity ◽  
Beta Adrenoceptor ◽  
Beta Receptor

To study the functional maturity of beta-receptor-mediated responses, seven chronically catheterized lamb fetuses, 93-107 days of gestation, and seven fetuses, 116-134 days of gestation, received intravenous randomly sequenced infusions of isoproterenol (ISO) 0.03, 0.06, and 0.125 micrograms.kg-1.min-1 for 10 min separated by 45-min intervals or two saline infusions followed by 0.125 micrograms.kg-1.min-1 ISO after treatment with 0.5 mg/kg propranolol (PRO). Each fetus received the two treatments 24-48 h apart. In immature fetuses, plasma renin activity (PRA) of 2.0 +/- 0.7 ng.ml-1.h-1 did not change with either protocol. In mature fetuses, PRA of 7.5 +/- 2.5 ng.ml-1.h-1 increased two- to three-fold after the infusion of the highest two doses of ISO (P less than 0.003). Propranolol blocked this response. No significant changes were observed after the infusions of the lowest dose of ISO or saline. Both groups showed significant heart rate increases with all doses of ISO. Propranolol injection decreased heart rate significantly and blocked responses to ISO. We conclude that although a cardiac beta-receptor-mediated response is present by 93 days of gestation in the lamb fetus, a renal beta-receptor-mediated response, renin secretion, is absent.

Solitary Kidney and Ageing as Causes of Low Renin and Aldosterone Concentrations: Relevance to ‘Low-Renin’ Essential Hypertension

1976 ◽  
Vol 51 (s3) ◽  
pp. 177s-180s ◽  
Author(s):  
R. Gordon ◽  
Freda Doran ◽  
M. Thomas ◽  
Frances Thomas ◽  
P. Cheras
Keyword(s):  
Blood Pressure ◽  
Essential Hypertension ◽  
Plasma Renin Activity ◽  
Plasma Volume ◽  
Plasma Renin ◽  
Renin Activity ◽  
Dietary Sodium ◽  
Sodium Restriction ◽  
Normotensive Subjects ◽  
The Mean

1. As experimental models of reduced nephron population in man, (a) twelve men aged 15–32 years who had one kidney removed 1–13 years previously and (b) fourteen normotensive men aged 70–90 years were studied. Results were compared with those in eighteen normotensive men aged 18–28 years and eleven men aged 19–33 years with essential hypertension. 2. While the subjects followed a routine of normal diet and daily activity, measurements were made, after overnight recumbency and in the fasting state, of plasma volume and renin activity on one occasion in hospital and of blood pressure on five to fourteen occasions in the home. Blood pressure was also measured after standing for 2 min and plasma renin activity after 1 h standing, sitting or walking. Twenty-four hour urinary aldosterone excretion was also measured. 3. The measurements were repeated in the normotensive subjects and subjects in (a) and (b) above after 10 days of sodium-restricted diet (40 mmol of sodium/day). 4. The mean plasma renin activity (recumbent) in essential hypertensive subjects was higher than in normotensive subjects. In subjects of (a) and (b) above, it was lower than normotensive subjects, and was not increased by dietary sodium restriction in subjects of (a). 5. The mean aldosterone excretion level was lower in old normotensive subjects than in the other groups, and increased in each group after dietary sodium restriction. 6. Mean plasma volume/surface area was not different between the four groups and in normotensive, essential hypertensive and nephrectomized subjects but not subjects aged 70–90 years was negatively correlated with standing diastolic blood pressure.

Renal Denervation Prevents Sodium Retention and Hypertension in Salt-Sensitive Rabbits with Genetic Baroreflex Impairment

1996 ◽  
Vol 90 (4) ◽  
pp. 287-293 ◽  
Author(s):  
Marta Weinstock ◽  
Elena Gorodetsky ◽  
Ronald Kalman
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Renin Activity ◽  
Renal Denervation ◽  
Plasma Renin ◽  
High Salt ◽  
Renin Activity ◽  
Group I ◽  
Group Ii

1. Rabbits with a genetic impairment in baroreflex control of heart rate become hypertensive on a high salt diet. The present study determined the effect of bilateral renal denervation on blood pressure and sodium balance after salt loading (four times normal intake; 28–36 mEq NaCl/day) in normotensive rabbits with high (Group I) and low (Group II) baroreflex sensitivity, respectively. 2. Eight rabbits in each group were denervated or sham-denervated 1 week before commencement of the high salt diet. Before operation, the two groups differed only in the gain of their cardiac baroreflex (Group I, −6.4 ± 0.4 beats min−1 mmHg−1; Group II, −3.2 ± 0.15 beats min−1 mmHg−1). 3. In Group I sham-denervated rabbits, mean arterial pressure remained unchanged, and plasma renin activity and heart rate fell significantly in response to the high salt. In Group II sham-denervated rabbits, mean arterial pressure increased by 10.6 ± 1.2 mmHg, and heart rate and plasma renin activity remained unchanged. Their cumulative Na+ retention and weight gain was more than twice that of Group I sham-denervated rabbits. 4. Renal denervation decreased plasma renin activity in both groups to <1 pmol Ang I h−1 ml−1, lowered cumulative Na+ retention from 102 ± 4 to 35 ± 5 mEq (P<0.01) and completely prevented the increase in mean arterial pressure in response to high salt in Group II. 5. The results suggest that Group II rabbits retain salt and fluid in response to their diet because of an abnormality in their control of renal nerve activity, possibly via vagal afferents. This results in blood pressure elevation because of an inability to lower peripheral resistance and heart rate in response to the increase in cardiac output. 6. Since they display several of the characteristics of salt-sensitive hypertensive humans, i.e. salt retention, normal plasma renin activity, but abnormal regulation of plasma renin activity and blood flow in response to salt loading, Group II are an appropriate model of human salt-induced hypertension.

Factors that alter the plasma renin activity of the marmot

1983 ◽  
Vol 244 (6) ◽  
pp. R823-R831
Author(s):  
W. J. Ray ◽  
M. L. Zatzman
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Mean Arterial Pressure ◽  
Plasma Renin Activity ◽  
Peripheral Resistance ◽  
Plasma Renin ◽  
Renin Activity ◽  
Low Doses ◽  
Control Data ◽  
Volume Load

The effects of low doses of norepinephrine (NE) and furosemide and a volume load (nonhibernators only) on plasma renin activity (PRA), mean arterial pressure (MAP), heart rate (HR), left renal (RBF) and right iliac (IBF) blood flow, cardiac index (CI), and total peripheral resistance (TPR) were determined in euthermic and hibernating marmots. In nonhibernating marmots NE produced an increase in CI and TPR and a decrease in RBF. In hibernators this dose of NE caused an increase in MAP, HR, and renal resistance, whereas it decreased PRA and did not alter iliac resistance. Furosemide infusions led to an increase in PRA in both groups and an increase in TPR in nonhibernators. The volume load in nonhibernators produced only a decrease in PRA. A comparison of control data from the two groups indicated that the renal and iliac beds contribute only a small portion to the increase in TPR that occurs during hibernation.

Role of vasopressin in blood pressure regulation in conscious water-deprived dogs

1983 ◽  
Vol 244 (1) ◽  
pp. R74-R77 ◽  
Author(s):  
J. Schwartz ◽  
I. A. Reid
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Renin Activity ◽  
Water Deprivation ◽  
Plasma Renin ◽  
Renin Activity ◽  
Pressure Regulation

The role of vasopressin in the regulation of blood pressure during water deprivation was assessed in conscious dogs with two antagonists of the vasoconstrictor activity of vasopressin. In water-replete dogs, vasopressin blockade caused no significant changes in mean arterial pressure, heart rate, plasma renin activity (PRA), or plasma corticosteroid concentration. In the same dogs following 48-h water deprivation, vasopressin blockade increased heart rate from 85 +/- 6 to 134 +/- 15 beats/min (P less than 0.0001), increased cardiac output from 2.0 +/- 0.1 to 3.1 +/- 0.1 1/min (P less than 0.005), and decreased total peripheral resistance from 46.6 +/- 3.1 to 26.9 +/- 3.1 U (P less than 0.001). Plasma renin activity increased from 12.4 +/- 2.2 to 25.9 +/- 3.4 ng ANG I X ml-1 X 3 h-1 (P less than 0.0001) and plasma corticosteroid concentration increased from 3.2 +/- 0.7 to 4.9 +/- 1.2 micrograms/dl (P less than 0.05). Mean arterial pressure did not change significantly. When the same dogs were again deprived of water and pretreated with the beta-adrenoceptor antagonist propranolol, the heart rate and PRA responses to the antagonists were attenuated and mean arterial pressure decreased from 103 +/- 2 to 91 +/- 3 mmHg (P less than 0.001). These data demonstrate that vasopressin plays an important role in blood pressure regulation during water deprivation in conscious dogs.

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