Effect of Propranolol on Blood Pressure and Renin in Renal Hypertension in the Rat

1977 ◽  
Vol 52 (1) ◽  
pp. 107-109
Author(s):  
M. Fernandes ◽  
G. Onesti ◽  
R. Fiorentini ◽  
A. B. Gould ◽  
K. E. Kim ◽  
...  

1. Propranolol was administered to groups of mature rats before and during the development of renal hypertension induced by ligation of the aorta between the renal arteries. 2. At a dose 10 μmol (3 mg) of propranolol/kg, administered by intraperitoneal injection, the onset and severity of hypertension were not affected, although plasma renin concentration was significantly lower than in the untreated hypertensive rats in the first 5 days after the operation. 3. With 200 μmol (60 mg) of propranolol/kg, administered in the drinking water, peak blood pressure 5 days after aortic ligation was lower than in the untreated control rats, but plasma renin concentration was no lower than with the smaller dose. 4. The development of severe hypertension despite reduction in plasma renin concentration on the low dose of propranolol suggests the participation of renal vasopressor factors other than renin in this model. 5. A higher dose of propranolol reduced the rise in plasma concentration to an equal extent but the rise of blood pressure at 5 days was also reduced, which supports this concept.

1998 ◽  
Vol 76 (1) ◽  
pp. 63-67 ◽  
Author(s):  
María Reverte ◽  
Olga Flores ◽  
Belén Gallego ◽  
Antonio Lestón ◽  
José Miguel López-Novoa

We have studied during 30 days the effect of a low dose of NG-nitro-L-arginine methyl ester (1 mg ·kg-1 ·day-1 in drinking water) in the presence of D- or L-arginine (1 mg ·kg-1 ·day-1 in drinking water) in comparison with D- or L-arginine alone on blood pressure and renal function in conscious uninephrectomized female spontaneously hypertensive rats. At the end of the study, there was a significant increase in systolic blood pressure in the NG-nitro-L-arginine methyl ester + D-arginine group (307 ± 6 mmHg (1 mmHg = 133.3 Pa), n = 14, p << 0.05) in comparison with NG-nitro-L-arginine methyl ester + L-arginine (281 ± 6 mmHg, n = 14), L-arginine (262 ± 5 mmHg, n = 13), and D-arginine (258 ± 7 mmHg, n = 12) groups. There were no changes in diuresis, proteinuria, or sodium and potassium excretion between differently treated animals during this study. These results suggest that in uninephrectomized female spontaneously hypertensive rats, after 1 month blockade of NO synthesis with a low dose of NG-nitro-L-arginine methyl ester, vasculature is under tonic control by NO and it is not correlated with renal dysfunction.Key words: Key words: NG -nitro-L-arginine methyl ester (L-NAME), kidney, hypertension, spontaneously hypertensive rats, renaldysfunction, uninephrectomy.


1981 ◽  
Vol 61 (s7) ◽  
pp. 335s-338s ◽  
Author(s):  
R. F. Bing ◽  
G. I. Russell ◽  
J. D. Swales ◽  
H. Thurston ◽  
A. Fletcher

1. Chemical renal medullectomy was produced in rats by injection of 2-bromoethylamine hydrobromide. Plasma creatinine and blood pressure were unchanged although urine volume was increased fourfold. 2. Left renal artery constriction resulted in similar degrees of hypertension in both intact and medullectomized rats. This was associated with a significantly smaller rise in plasma renin concentration in the latter. 3. Blood pressure in conscious intact hypertensive rats became normal within 24 h of unclipping whereas blood pressure of medullectomized rats remained significantly elevated. 4. The presence of an intact renal medulla is essential to the complete reversal of two-kidney, one-clip hypertension in the rat. This may reflect the loss of a medullary vasodepressor system.


Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Nirupama Ramkumar ◽  
Deborah Stuart ◽  
Matias Calquin ◽  
Shuping Wang ◽  
Fumio Niimura ◽  
...  

It is unknown if intrarenal generation of angiotensinogen (AGT) is important in blood pressure (BP) regulation. Previous studies showed that proximal tubule-specific overexpression of AGT increases BP, while proximal tubule-specific deletion of AGT using the KAP promoter-Cre transgene did not alter BP. The latter study may not have completely eliminated nephron AGT production; in addition, BP was only assessed on a normal salt diet. To evaluate this issue in greater detail, we developed mice with inducible nephron-wide AGT deletion. Mice were generated which were hemizygous for the Pax8-rtTA and LC-1 transgenes and homozygous for loxP flanked AGT alleles to achieve nephron-specific AGT disruption after doxycycline induction. Adult Pax8-rtTA/LC-1/floxed AGT mice at 3 months of age were treated with doxycycline 2 mg/ml in drinking water for 11 days and studied 4 weeks after treatment. Blood pressure (recorded via telemetry) and metabolic balance studies were determined during 5 days of normal, high and low Na diets. Compared to controls, AGT knockout (KO) mice demonstrated significantly lower systolic, diastolic, and mean BPs on all three diets (N=4 each group). The BP reduction was most evident on a low Na diet (mean BP 107 ± 2 mmHg in controls and 88 ± 13 mmHg in AGT KO). Plasma renin concentration was higher in the AGT KO mice as compared to controls on all three diets. There were no detectable differences in weight, urine volume, urine osmolality or urine Na excretion between the controls and KO mice on all three diets, however due to variability, small differences in these parameters may not have been detected. Taken together, these data suggest that nephron AGT may contribute to BP regulation and this is most evident during low Na intake.


1973 ◽  
Vol 45 (s1) ◽  
pp. 251s-255s ◽  
Author(s):  
G. Dauda ◽  
J. Möhring ◽  
K. G. Hofbauer ◽  
E. Homsy ◽  
Ulrike Miksche ◽  
...  

1. In renal hypertensive rats, increase in blood pressure above 180 mmHg may induce sodium and water loss, reduced growth rate, elevated haematocrit, a marked rise in plasma renin concentration, an increase in renin extractable from the clamped and the contralateral kidney and malignant nephrosclerosis of the contralateral kidney. These symptoms characterize the malignant phase of renal hypertension in rats. 2. When water was given as drinking fluid, ten of eighteen rats developed signs of malignant hypertension and malignant nephrosclerosis within 3–4 weeks. Administration of 0.9% saline instead of water induced higher blood-pressure levels, but only five of eighteen rats showed malignant nephrosclerosis. When drinking fluid was changed from water to saline shortly before or shortly after the onset of malignant hypertension, the condition improved, and in only one of twelve rats was malignant nephrosclerosis observed. 3. It is concluded that in renal hypertensive rats sodium supplements may improve or prevent signs of malignant hypertension and the development of malignant nephrosclerosis.


1977 ◽  
Vol 18 (3) ◽  
pp. 392-397 ◽  
Author(s):  
Chun Ho PAK ◽  
Masato MATSUNAGA ◽  
Jin YAMAMOTO ◽  
Jun KIRA ◽  
Koichi OGINO ◽  
...  

1980 ◽  
Vol 238 (1) ◽  
pp. E53-E61 ◽  
Author(s):  
D. J. Eakin ◽  
L. A. Schroeder ◽  
P. D. Whanger ◽  
P. H. Weswig

Weanling rats were fed a casein-based diet containing either 150 ppm cadmium, 500 ppm nickel, or the combination of these metals for 16 wk. Blood pressure of rats fed the diet with cadmium decreased after 8 wk, but this effect was counteracted by dietary nickel. Cadmium caused a depletion of iron and resulted in an accumulation of zinc in liver and kidney of rats. Nickel partially counteracted the iron loss due to cadmium. In a second experiment, the inclusion of 10 or 20 ppm cadmium in drinking water for 24 mo did not result in elevated blood pressure in normal or genetically hypertensive rats. Cadmium had no effect on the plasma renin levels in either experiment. Low intake of cadmium (10 or 20 ppm) in drinking water resulted in elevated cadmium content in hair. Thus, our data do not indicate that high levels of cadmium contribute to hypertension.


1998 ◽  
Vol 95 (4) ◽  
pp. 445-451 ◽  
Author(s):  
Rachel OKUNIEWSKI ◽  
Elizabeth A. DAVIS ◽  
Bevyn JARROTT ◽  
Robert E. WIDDOP

1.The objective of this study was to determine the influence of gender on the development of renal hypertension in Sprague–Dawley rats using the Goldblatt two-kidney, one-clip (2K1C) model. In addition, this study examined the effect of ovariectomy upon the development of hypertension in female rats. 2.At 10 weeks of age, male, intact female and ovariectomized female rats underwent clipping of the right renal artery or sham operation. Tail-cuff plethysmography was used to monitor the systolic blood pressure of all animals for 7 weeks post-clipping or sham operation. Rats were sub-grouped according to whether or not they developed hypertension (systolic blood pressure ⩾ 150 ;mmHg). 3.Within 2 to 3 weeks of clipping, hypertension was induced in only 53% (n = 120) of the intact female 2K1C rats, but in 83% (n = 18) of the male and 78% (n = 18) of the ovariectomized female rats. 4.Seven weeks after right renal artery clipping, plasma renin activity was determined in a subset of each group and was found to be 5–6 fold higher in male (17.29±4.04 ;ng angiotensin I·h-1·ml-1) and ovariectomized female (9.71±1.25 ;ng angiotensin I·h-1·ml-1) hypertensive rats compared with their respective normotensive or sham-operated counterparts (3.39±0.58 ;ng angiotensin I·h-1·ml-1 and 1.60±0.41 ;ng angiotensin I·h-1·ml-1 respectively) (P< 0.05, analysis of variance). In contrast, the plasma renin activity measured in intact female hypertensive rats was not significantly different from that measured in the corresponding 2K1C normotensive or sham-operated groups. 5.These results indicate that the success rate of inducing renal hypertension in Sprague–Dawley rats is higher in males than in intact females. Furthermore, these results suggest that the induction of 2K1C hypertension may be influenced by ovarian hormones.


1975 ◽  
Vol 48 (1) ◽  
pp. 17-26 ◽  
Author(s):  
F. H. H. Leenen ◽  
J. W. Scheeren ◽  
D. Omylanowski ◽  
J. D. Elema ◽  
B. Van Der Wal ◽  
...  

1. The relationships between the renin-angiotensin-aldosterone system, sodium and potassium balance and systolic blood pressure were studied during development of moderate (160–180 mmHg; clip i.d. 0.25 mm) and severe (200–230 mmHg; clip i.d. 0.20 mm) renal hypertension in rats with an undisturbed contralateral kidney. 2. In severely hypertensive rats renin activity in the peripheral plasma increased from day 9, by which time the systolic blood pressure was elevated to 160–180 mmHg. The rate of total corticosteroid and aldosterone production in vitro increased from day 14 and plasma renin substrate concentration increased from day 24. In moderately hypertensive rats, none of these changes occurred. 3. During the first 10 days after the application of 0.25 and 0.20 mm clips, sodium and potassium retention/g gain in body weight were higher than in sham-operated controls. During the next 10 days, the positive balance stabilized in animals with a 0.25 mm clip whereas, in animals with a 0.20 mm clip, sodium and potassium balance returned to the level of the sham-operated controls through increased renal losses. Despite these changes the systolic pressure rose further in animals with a 0.20 mm clip. 4. The initial sodium retention could be a factor in the early rise of blood pressure and could account for the delay in the rise of peripheral plasma renin activity. The subsequent loss of the retained sodium and potassium during the development of severe hypertension could have facilitated the rise in peripheral plasma renin activity, but did not initiate this rise.


1979 ◽  
Vol 57 (1) ◽  
pp. 25-29 ◽  
Author(s):  
G. Bellini ◽  
R. Fiorentini ◽  
M. Fernandes ◽  
G. Onesti ◽  
H. Hessan ◽  
...  

1. Pentolinium tartrate (a ganglionic blocker) was injected in conscious rats during the early and late phases of two-kidney renal hypertension produced by aortic ligation. 2. In the early phase (5 days after aortic ligation), ganglionic blockade resulted in a decrease in blood pressure equal to that obtained in normotensive rats. Later, at days 12 and 40, for equally severe hypertension, ganglion blockade resulted in a greater decrease in blood pressure. 3. A 30 min infusion of [Sar1, Ala8]angiotensin II during the pentolinium-induced nadir in blood pressure resulted in a further decrease in blood pressure at day 5. Later, at days 12 and 40, this effect was smaller. 4. A 300 min infusion of [Sar1, Ala8]angiotensin II normalized the blood pressure in hypertensive rats at day 40. This delayed response may be secondary to a central effect of the antagonist, reducing neurogenic tone or peripheral antagonism of locally generated angiotensin II in the blood vessel walls. 5. At day 40, removal of the small left kidney resulted in a greater decrease in blood pressure. This suggests the presence of a renal factor other than renin in the chronic phase of this hypertension.


1984 ◽  
Vol 246 (4) ◽  
pp. H573-H578
Author(s):  
B. Waeber ◽  
J. Nussberger ◽  
H. R. Brunner

A total of 75 male Wistar rats with one-kidney, one-clip renal hypertension was maintained on either a regular (RNa) or a low-salt (LNa) diet for 3 wk after clipping. Blood pressure in the unanesthetized rats was equally elevated independent of sodium intake. Plasma renin activity was higher in LNa animals, and blood pressure was renin dependent only in this group, as evidenced by the blood pressure response to 10 mg/kg captopril iv. There was no significant difference in plasma catecholamines between RNa and LNa rats, although in the former the sympathetic nervous system is believed to play a major role in sustaining high blood pressure. The acute intravenous administration of 0.5 mg/kg prazosin did not induce a more pronounced blood pressure fall in the RNa rats. Prazosin enhanced plasma norepinephrine levels similarly in both groups, but epinephrine levels only rose in the LNa animals. Prazosin also markedly stimulated plasma renin activity rendering blood pressure renin dependent even in RNa rats. Thus, using alpha 1-adrenoceptor blockade, it has not been possible to demonstrate that the blood pressure elevation of salt-repleted one-kidney, one-clip renal hypertensive rats is due to an enhanced sympathetic nerve activity. Data obtained with sympatholytic agents must be interpreted with great caution if renin activity cannot be kept unchanged.


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