The Vicious Circle in Acute Malignant Hypertension of Rats

1973 ◽  
Vol 45 (s1) ◽  
pp. 251s-255s ◽  
Author(s):  
G. Dauda ◽  
J. Möhring ◽  
K. G. Hofbauer ◽  
E. Homsy ◽  
Ulrike Miksche ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renal Hypertension ◽  
Plasma Renin ◽  
Malignant Hypertension ◽  
Hypertensive Rats ◽  
Marked Rise ◽  
Contralateral Kidney ◽  
Renal Hypertensive Rats ◽  
Malignant Nephrosclerosis ◽  
Drinking Fluid

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.

Plasma Renin Activity and Sodium, Potassium and Water Excretion during Reversal of Hypertension in the One-Clip, Two-Kidney Hypertensive Rat

1979 ◽  
Vol 57 (1) ◽  
pp. 47-52 ◽  
Author(s):  
R. G. M. Ten Berg ◽  
F. H. H. Leenen ◽  
W. De Jong
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Renin Activity ◽  
Internal Diameter ◽  
Hypertensive Rats ◽  
Water Excretion ◽  
Contralateral Kidney ◽  
Sodium And Potassium ◽  
Renal Hypertensive Rats

1. The effect of removal of the clip on blood pressure, plasma renin activity and the excretion of water, sodium and potassium was studied in renal hypertensive rats. Hypertension was induced by application of a clip with an internal diameter of 0·20 mm, which was removed after 1, 2 or 3 weeks, and by using a clip with an internal diameter of 0·25 mm, which was removed after 2 weeks. The contralateral kidney remained undisturbed. 2. Blood pressure was almost normal 24 h after the removal of the clip; 70–90% of the total decrease in blood pressure occurred within 2–5 h. 3. The increased plasma renin activity, which was observed 2 and 3 weeks after application of a 0·20 mm clip, had returned to control values 24 h after removal of the clip. One week after application of a 0·20 mm clip, and 2 weeks after a 0·25 mm clip, plasma renin activity did not differ significantly from control values, before as well as after unclipping. 4. No significant differences were found between unclipped and sham-operated renal hypertensive rats, nor between the latter and the sham-operated normotensive control rats for water, sodium and potassium excretion, and for change in body weight, during the 24 h after the removal of the clip. 5. It is concluded that urinary loss of water and/or sodium does not play an important role in the acute decrease of blood pressure which occurs after the removal of a renal artery clip in one-clip, two-kidney hypertensive rats. A decrease in peripheral plasma renin activity can only partly explain the reversal of the hypertension.

ALDOSTERONE AND CORTICOSTERONE PRODUCTION IN RENAL HYPERTENSIVE RATS

1975 ◽  
Vol 79 (2) ◽  
pp. 317-328 ◽  
Author(s):  
R. Dietz ◽  
G. J. Mast ◽  
J. Möhring ◽  
P. Vecsei ◽  
K. H. Gless ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renal Artery ◽  
Renal Hypertension ◽  
Plasma Concentrations ◽  
Plasma Aldosterone ◽  
Malignant Hypertension ◽  
Hypertensive Rats ◽  
Plasma Aldosterone Concentration ◽  
Contralateral Kidney ◽  
Aldosterone Production

ABSTRACT The development of hypertension, which had been elicited by clamping one renal artery in the presence of an untouched contralateral kidney, has been pursued in rats for up to six weeks after operation, and aldosterone and corticosterone production was studied at various intervals. Two weeks after renal artery stenosis had been induced, a "benign" and a "malignant" course of hypertension could be distinguished, the latter being characterized by a rise in blood pressure beyond 180–190 mmHg, loss of salt and water, increased water intake, decrease in body weight and food intake, and stimulation of the renin-angiotensin system. In the early phase of hypertension (after 9 days), aldosterone production and plasma aldosterone concentration were already elevated, and so was plasma corticosterone concentration. After 16 days, a marked increase in aldosterone production and in both plasma aldosterone and corticosterone concentrations was obtained in malignant hypertensive rats, whereas the secretion of the two hormones was only slightly stimulated in benign hypertensive rats. Similar differences in aldosterone production between rats with benign or malignant hypertension were found 21 and 42 days after operation. After 21 days, a close relationship between plasma renin concentration and aldosterone production was obtained in malignant hypertensive and control rats. A positive correlation between plasma concentrations of angiotensin II and of aldosterone was calculated for rats with malignant hypertension. It is concluded that, in the malignant phase of renal hypertension, a state of secondary aldosteronism develops as a consequence of negative sodium and water balance induced by high blood pressure.

Effect of Ureteral Ligation of the Contralateral Kidney on Angiotensin Dependency in One-Clip, Two-Kidney Renal Hypertensive Rats

1982 ◽  
Vol 63 (s8) ◽  
pp. 211s-213s
Author(s):  
Yutaka Takata ◽  
Austin E. Doyle ◽  
Margherita Veroni ◽  
Stuart G. Duffy
Keyword(s):  
Blood Pressure ◽  
Oral Administration ◽  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Hypertensive Rats ◽  
Excretory Function ◽  
Contralateral Kidney ◽  
Single Oral Administration ◽  
Renal Hypertensive Rats ◽  
Renin Content

1. The aim of this study was to determine whether the urinary excretory function of the contralateral kidney is essential for angiotensin dependency in two-kidney, one-clip renal hypertensive rats. Ureteric ligation was used to abolish excretion from the contralateral kidney. 2. Plasma renin activity (PRA), renal renin content (RRC) and the response of blood pressure to captopril were examined. 3. The increase of blood pressure produced by the application of a clip to one renal artery was slightly accelerated by the ureteral ligation of the contralateral kidney. 4. Ureteral ligation of the contralateral kidney did not alter the response to a single oral administration of captopril. PRA and RRC of both kidneys were not different between the ureteral ligated group and the group without ureteric ligation. The falls in blood pressure produced by captopril correlated with PRA in the two groups. 5. These results suggest that the excretory function of the contralateral kidney is not essential for angiotensin dependency in the two-kidney, one-clip hypertensive rat model.

Alpha 1-adrenoceptor blockade in renal hypertensive rats with low and high renin levels

1984 ◽  
Vol 246 (4) ◽  
pp. H573-H578
Author(s):  
B. Waeber ◽  
J. Nussberger ◽  
H. R. Brunner
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Renal Hypertension ◽  
Plasma Renin ◽  
Renin Activity ◽  
Plasma Norepinephrine ◽  
Hypertensive Rats ◽  
Blood Pressure Elevation ◽  
Significant Difference ◽  
Renal Hypertensive Rats

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.

Renin-angiotensin system in stroke-prone spontaneously hypertensive rats

1979 ◽  
Vol 236 (3) ◽  
pp. H409-H416 ◽  
Author(s):  
M. Shibota ◽  
A. Nagaoka ◽  
A. Shino ◽  
T. Fujita
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Malignant Hypertension ◽  
Hypertensive Rats ◽  
Salt Loading ◽  
Angiotensin System ◽  
Spontaneously Hypertensive ◽  
Renin Angiotensin

The development of malignant hypertension was studied in stroke-prone spontaneously hypertensive rats (SHR) kept on 1% NaCl as drinking water. Along with salt-loading, blood pressure gradually increased and reached a severe hypertensive level (greater than 230 mmHg), which was followed by increases in urinary protein (greater than 100 (mg/250 g body wt)/day) and plasma renin concentration (PRC, from 18.9 +/- 0.1 to 51.2 +/- 19.4 (ng/ml)/h, mean +/- SD). At this stage, renal small arteries and arterioles showed severe sclerosis and fibrinoid necrosis. Stroke was observed within a week after the onset of these renal abnormalities. The dose of exogenous angiotensin II (AII) producing 30 mmHg rise in blood pressure increased with the elevation of PRC, from 22 +/- 12 to 75 +/- 36 ng/kg, which was comparable to that in rats on water. The fall of blood pressure due to an AII inhibitor, [1-sarcosine, 8-alanine]AII (10(microgram/kg)/min for 40 min) became more prominent with the increase in PRC in salt-loaded rats, but was not detected in rats on water. These findings suggest that the activation of renin-angiotensin system participates in malignant hypertension of salt-loaded stroke-prone SHR rats that show stroke signs, proteinuria, hyperreninemia, and renovascular changes.

Renin content and excretory function of the kidney in rats with experimental hypertension

1962 ◽  
Vol 202 (4) ◽  
pp. 795-799 ◽  
Author(s):  
H. Brunner ◽  
P. A. Desaulles ◽  
D. Regoli ◽  
F. Gross
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Renal Hypertension ◽  
Experimental Hypertension ◽  
Elevated Blood ◽  
Hypertensive Rats ◽  
Excretory Function ◽  
Contralateral Kidney ◽  
Ligation Of The Ureter ◽  
Renin Content

To determine relationship between kidney renin content and excretory function, rats with renal hypertension induced by unilateral clamping of the renal artery were given an oral load of 3 ml of 0.9% saline/100 g body wt. Excretion of the saline load was accelerated in rats with renal hypertension as well as in animals with hypertension due to overdosage with cortexone and salt, provided that the loading experiment was made 3–4 weeks after hypertension was established, but not when animals had been hypertensive for 11–14 weeks. Renin concentration was markedly reduced in the unclamped kidney and also in the kidney of the rats overdosed with cortexone and salt. Excreting capacity of the clamped kidney was compared with that of the unclamped kidney, after removal or after functional elimination of the contralateral kidney, by ligation of the ureter, 3, 24, and 48 hr after the operation. In all experiments excretion of saline load by the unclamped kidney was more rapid than by the clamped kidney, but the highest values were reached in the presence of a functional clamped kidney. Only in rats with elevated blood pressure was the load more rapidly excreted than in normal rats, but hypertension alone cannot be the only factor responsible, the excretion not being accelerated in unilaterally nephrectomized hypertensive rats. Although these hint at a connection between the renin concentration and renal function the nature of this relationship remains uncertain.

Quantitative assay and disappearance rate of circulating renin

1964 ◽  
Vol 206 (6) ◽  
pp. 1361-1364 ◽  
Author(s):  
G. Schaechtelin ◽  
D. Regoli ◽  
F. Gross
Keyword(s):  
Blood Pressure ◽  
Blood Pressure Response ◽  
Pressure Response ◽  
Pressure Increase ◽  
Disappearance Rate ◽  
Hypertensive Rats ◽  
Contralateral Kidney ◽  
Blood Pressure Increase ◽  
Hypertensive Animal ◽  
Renal Hypertensive Rats

In isovolemic cross-circulation experiments, a nephrectomized donor rat, into which various doses of hog renin were injected, was connected to a nephrectomized indicator rat. The blood pressure increase thus produced in the indicator rat was compared with the blood pressure response obtained during cross circulation using either intact normotensive or renal hypertensive rats as donor animals. An exponential dose-response relationship was found between hog renin injected into a nephrectomized donor and the blood pressure increase of the indicator rat. Using the cross-circulation technique, the disappearance rate of endogenous reninlike material in the blood of donor animals and of exogenous renin injected into nephrectomized donor animals was examined. If an intact normotensive animal or a unilaterally nephrectomized hypertensive animal is totally nephrectomized, reninlike material disappears from the blood within 1 hr. In renal hypertensive rats with an untouched contralateral kidney which have a higher concentration of reninlike material in the blood, it takes about twice the normal time until reninlike material disappears from the blood after nephrectomy. The increased and prolonged blood pressure response of the nephrectomized animal to renin is not connected with a prolonged persistence of renin in the blood.

Anti-hypertension Effects of Traditional Chinese Medicine Ju-Ling-Tang on Renal Hypertensive Rats

2005 ◽  
Vol 33 (06) ◽  
pp. 913-921 ◽  
Author(s):  
Hung-Che Shih ◽  
Tzu-Hsin Lee ◽  
Shu-Chen Chen ◽  
Chien-Ying Li ◽  
Takeshi Shibuya
Keyword(s):  
Blood Pressure ◽  
Animal Model ◽  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Renal Hypertension ◽  
Tube Feeding ◽  
Glomerular Sclerosis ◽  
Hypertensive Rats ◽  
Artery Ligation ◽  
Renal Hypertensive Rats

This research investigated the anti-hypertension effect of the traditional Chinese medicine (TCM) Ju-Ling-Tang (JLT) on an animal model of hypertension induced by unilateral renal artery ligation. In the study of anti-hypertension effects, 60 minutes after oral administration with NG tube feeding of 240 mg/kg JLT, a significant decrease in blood pressure ( p < 0.05) was observed and sustained till 120 minutes. In the group given 50 mg/kg α-methyldopa orally, the effect was obvious 90 minutes after medication ( p < 0.01), and lasted until 240 minutes. In terms of organ pathology, a significant reduction in the extent of induced glomerular sclerosis was observed in rats given 240 mg/kg JLT compared with the control. From these results, we infer that JLT has a beneficial anti-hypertensive effect on renal hypertension.

EFFECTS OF EXPERIMENTAL RENAL HYPERTENSION ON ALDOSTERONE BIOSYNTHESIS BY RAT ADRENAL TISSUE

1969 ◽  
Vol 60 (4) ◽  
pp. 669-680 ◽  
Author(s):  
J. Müller ◽  
F. Gross
Keyword(s):  
Renal Artery ◽  
Renal Hypertension ◽  
Plasma Renin ◽  
Renin Activity ◽  
Sodium Deficiency ◽  
Marked Rise ◽  
Contralateral Kidney ◽  
Aldosterone Production ◽  
Experimental Renal Hypertension

ABSTRACT Aldosterone biosynthesis by quartered adrenal glands from rats with different forms of experimental renal hypertension due to clamping of one renal artery, was studied under various in vitro conditions. During incubation without aldosterone-stimulating substances, the adrenals of rats with one renal artery clamped and the other kidney left intact produced 200 % more aldosterone from endogenous precursors and converted 50 % more added tritium-labelled pregnenolone, progesterone or corticosterone to aldosterone than adrenals of control animals. The difference in aldosterone production was less marked when serotonin, KCl or ACTH was added to the incubation medium. The production of corticosterone and of deoxycorticosterone, respectively, was almost the same in adrenals of both groups of rats under most in vitro conditions. The marked rise in aldosterone production seen in the presence of an intact contralateral kidney was partially or completely inhibited, when simultaneously with renal artery constriction, the contralateral kidney was removed or the ureter of either the clamped or the contralateral kidney was ligated. These results indicate that in rats with experimental renal hypertension, increases in aldosterone production are correlated with increases of plasma renin activity and of the renin content of the clamped kidney, but are independent of changes in blood pressure. Since chronically elevated levels of plasma or renal renin activity act mainly in the early stages of aldosterone biosynthesis, it is concluded that the marked activation in the final stages of aldosterone biosynthesis observed in sodium deficiency is not mediated by the renin-angiotensin system.

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 ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Drinking Water ◽  
Plasma Concentration ◽  
Low Dose ◽  
Severe Hypertension ◽  
Renal Hypertension ◽  
Plasma Renin ◽  
Hypertensive Rats ◽  
Plasma Renin Concentration ◽  
Peak Blood

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.

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