Salt and water balance and renin activity in renal hypertension of rats

1975 ◽  
Vol 228 (6) ◽  
pp. 1847-1855 ◽  
Author(s):  
J Mohring ◽  
B Mohring ◽  
H-J Naumann ◽  
A Philippi ◽  
E Homsy ◽  
...  
Keyword(s):  
Water Balance ◽  
Renal Artery ◽  
Renal Hypertension ◽  
The Body ◽  
Renin Activity ◽  
Sodium Balance ◽  
Sprague Dawley ◽  
Contralateral Kidney ◽  
Salt And Water Balance ◽  
Renal Artery Constriction

In male Sprague-Dawley rats, renal artery constriction in the presence of an inact contralateral kidney induced sodium retention (for 2-3 wk), moderate potassium loss,elevation of blood volume (BV), and an increase in water turnover. It is suggestedthat renal artery constriction activates the renin-angiotensin-aldosterone system, resulting in disordered regulation of salt and water balance and in blood pressure (BP) elevation. Subsequently, sodium balance was reestablished in one group of hypertensive rats. The previously retained sodium was kept in the body, and BV and reninactivity remained elevated. In a second group of animals, a malignant course of hypertension developed: BP surpassed a critical level of about 180 mmHg; sodium, potassium, and water were lost; BV declined; renin activity was further stimulated; and in the contralateral kidney malignant nephrosclerosis occurred. It is assumed that pressure diuresis and natriuresis induce a vicious circle: the increasing renin activity may maintain or further increase BP level, therby inducing further salt and water loss, etc.; high BP levels and high renin activities induce vascular damage and deterioration of renal function.

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.

scholarly journals Salt and Water Balance in the East African Fresh-Water Crab, Potamon Niloticus (M. Edw.)

1959 ◽  
Vol 36 (1) ◽  
pp. 157-176 ◽  
Author(s):  
J. SHAW
Keyword(s):  
Water Balance ◽  
Fresh Water ◽  
Sea Water ◽  
Freezing Point ◽  
Salt Content ◽  
The Body ◽  
Sodium Balance ◽  
East African ◽  
Sodium Loss ◽  
Salt And Water Balance

1. The mechanisms of salt and water balance in the East African fresh-water crab, Potamon niloticus, have been investigated. 2. The freezing-point depression of the blood is equivalent to that of a 271 mM./l. NaCl solution. 3. The animals cannot survive in solutions more concentrated than 75% sea water. Above the normal blood concentration, the blood osmotic pressure follows that of the medium. 4. The urine is iso-osmotic with the blood and is produced at a very slow rate. The potassium content is only half that of the blood. 5. The animal loses sodium at a rate of 8 µM./10 g./hr. mainly through the body surface. Potassium loss occurs at one-sixteenth of this rate. 6. Sodium balance can be maintained at a minimum external concentration of 0.05 mM./l. Potassium requires a concentration of 0.07 mM./l. 7. Active absorption of both sodium and potassium occurs. The rate of uptake of sodium depends on the extent of previous sodium loss. The rate of sodium uptake may be affected by such environmental factors as the salt content of the water, temperature and oxygen tension. 8. The normal oxygen consumption rate is 0.72 mg./10 g./hr. A minimum of 2.3% is used in doing osmotic work to maintain salt balance. 9. The salt and water balance in Potamon is discussed in relation to the adaptation of the Crustacea to fresh water. The importance of permeability changes is stressed.

Inhibition of angiotensin conversion and prevention of renal hypertension

1975 ◽  
Vol 228 (2) ◽  
pp. 448-453 ◽  
Author(s):  
Miller ED ◽  
AI Samuels ◽  
E Haber ◽  
AC Barger
Keyword(s):  
Blood Pressure ◽  
Renal Artery ◽  
Renovascular Hypertension ◽  
Renal Hypertension ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Renin Activity ◽  
Angiotensin System ◽  
The One ◽  
Renal Artery Constriction

Renal artery constriction in the unilaterally nephrectomized, trained dog, with maintained renal arterial hypotension, produces a prompt increase in systemic renin activity and blood pressure. The hypertension normally induced by renal artery stenosis is prevented by prior treatment with the nonapeptide Pyr-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro (SQ 20, 881), which blocks conversion of angiotensin I to angiotensin II. Constant intravenous infusion of the inhibitor over several days of renal artery constriction prevents the development of chronic renovascular hypertension. Furthermore, a single injection of the nonapeptide restores blood pressure to normal in the early phase of renovascular hypertension, but becomes progressively less effective as salt and water retention occurs in the chronic stage when plasma renin activity returns to control levels. These data provide strong evidence that the renin-angiotensin system is responsible for the initiation of renovascular hypertension in the one-kidney Goldblatt dog, but that other factors become increasingly important in chronic renovascular hypertension.

Evidence for a Significant Contribution from Central Effects of Angiotensin in the Development of Acute Renal Hypertension in the Greyhound

1975 ◽  
Vol 48 (2) ◽  
pp. 115-119 ◽  
Author(s):  
G. C. Scroop ◽  
F. P. Katic ◽  
M. J. Brown ◽  
M. D. Cain ◽  
P. J. Zeegers
Keyword(s):  
Plasma Renin Activity ◽  
Renal Artery ◽  
Significant Role ◽  
Significant Contribution ◽  
Renal Hypertension ◽  
Plasma Renin ◽  
Renin Activity ◽  
Central Effects ◽  
Renal Artery Constriction

1. The importance of central vasomotor effects of endogenously generated angiotensin in the acute hypertensive response to renal artery constriction has been investigated in the anaesthetized greyhound. 2. When the central cardiovascular action of angiotensin was abolished by thermocoagulation of the areas postrema, the hypertensive response to renal artery constriction was reduced by half while the increase in plasma renin activity was unchanged. 3. It is concluded that central vasomotor effects of angiotensin play a significant role in renin-dependent hypertension.

Experimental Renal Hypertension: Renin Content of Kidneys in Intact and Adrenalectomized Rats Given Cortexone

1958 ◽  
Vol 195 (3) ◽  
pp. 543-548 ◽  
Author(s):  
F. Gross ◽  
P. Lichtlen
Keyword(s):  
Renal Artery ◽  
Renal Hypertension ◽  
Normal Animal ◽  
Renal Ischemia ◽  
Characteristic Distribution ◽  
Contralateral Kidney ◽  
Moderate Reduction ◽  
Small Doses ◽  
Experimental Renal Hypertension ◽  
Renin Content

The effects were investigated in rats of unilateral renal ischemia, adrenalectomy and varying doses of cortexone on the development of hypertension and on the content of pressor substances in the kidney. Adrenalectomy prevented the hypertension which follows unilateral clamping of the renal artery when a life maintaining dose of 0.1 mg cortexone acetate was injected daily. However, administration of 75 mg cortexone in the form of implants restored but did not enhance the characteristic hypertensive response to renal ischemia. The characteristic distribution of renal pressor material, being normal in the clamped and diminished in the contralateral kidney, was no longer observed after adrenalectomy when only small doses of cortexone were given but was still evident when excess cortexone was given. Overdosage with cortexone without clamping a renal artery led only to a moderate reduction of pressor material in both kidneys while in animals with unilateral renal ischemia the pressor material (renin?) in the contralateral kidney disappeared completely. Clamping the renal artery prevented the diminution of pressor material in the ipsilateral kidney which otherwise occurs under overdosage with cortexone in the normal animal.

Development of chronic perinephritic hypertension in dogs without volume expansion

1977 ◽  
Vol 233 (4) ◽  
pp. F278-F281 ◽  
Author(s):  
R. H. Freeman ◽  
J. O. Davis ◽  
B. E. Watkins
Keyword(s):  
Cardiac Output ◽  
Arterial Pressure ◽  
Volume Expansion ◽  
Left Kidney ◽  
Renal Hypertension ◽  
Control Level ◽  
Whole Body ◽  
Sodium Balance ◽  
Contralateral Kidney ◽  
Experimental Renal Hypertension

The theory of whole body autoregulation to explain the pathogenesis of experimental renal hypertension states that hypertension is initiated in response to an early increase in salt and water retention and a subsequent elevation of the cardiac output. This hypothesis was evaluated in the present study. Dogs (n,5) were made hypertensive by wrapping the left kidney in cellophane and removing the contralateral kidney 3 wk later. One week prior to right nephrectomy, the dogs were volume depleted by placing them on a low sodium intake (less than 3 meq of sodium/day) and giving them a mercurial diuretic for the first 3 days of the diet. This superimposed sodium depletion (negative sodium balance of 137 +/- 17 meq) increased plasma renin activity 3-5 times but did not change arterial pressure or heart rate. Within 2 days after nephrectomy, the mean arterial pressure increased from the control level of 105 +/- 1 to 135 +/- 6 mmHg (P less than 0.005) and pressure remained elevated throughout an additional 4-wk period in which volume depletion was enforced. The present study suggests, therefore, that initial blood volume expansion with such possible consequences as elevated cardiac output are not essential to the pathogenesis of experimental renal hypertension.

Studies on Salt and Water Balance in Caddis Larvae (Trichoptera)

1961 ◽  
Vol 38 (3) ◽  
pp. 501-519 ◽  
Author(s):  
D. W. SUTCLIFFE
Keyword(s):  
Water Balance ◽  
Sea Water ◽  
Salt Water ◽  
Chloride Concentration ◽  
Malpighian Tubule ◽  
Free Water ◽  
The Body ◽  
Chloride Uptake ◽  
Concentrated Solution ◽  
Salt And Water Balance

1. Limnephilus affinis larvae tolerate external salt concentrations up to at least 410 mM./l. NaCl (about 75% sea water) and survive for short periods in 470 mM./l. NaCl (about 85/ sea water). 2. The body wall is highly permeable to water, but relatively impermeable to sodium and chloride. Most of the sodium and chloride uptake from salt water occurs via the mouth. 3. The sodium and chloride levels in the haemolymph are powerfully regulated. Both are maintained strongly hypotonic against large external concentration gradients. 4. The Malpighian tubule-rectal system is very sensitive to changes in the haemolymph chloride level. The chloride concentration in the rectal fluid can be at least three times greater than the concentration in the haemolymph, and slightly greater than the concentration in the external medium. 5. The rectal fluid is hyper-osmotic to the haemolymph and to the medium at high external salt concentrations. 6. At external concentrations greater than about 200 mM./l. NaCl, water balance is maintained by regulating the haemolymph roughly iso-osmotic with the medium. This is partly achieved by increasing the non-electrolyte fraction in the haemolymph. A small quantity of osmotically free water is available to replace any osmotic loss. This can be obtained by drinking salt water and producing a concentrated solution of salts in the rectum.

scholarly journals Hemodynamic and neural responses to renal denervation of the nerve to the clipped kidney by cryoablation in two-kidney, one-clip hypertensive rats

2016 ◽  
Vol 310 (2) ◽  
pp. R197-R208 ◽  
Author(s):  
Noreen F. Rossi ◽  
Russell Pajewski ◽  
Haiping Chen ◽  
Peter J. Littrup ◽  
Maria Maliszewska-Scislo
Keyword(s):  
Renal Artery ◽  
Renal Denervation ◽  
Renal Tissue ◽  
Reflex Response ◽  
Ang Ii ◽  
Neural Responses ◽  
Sprague Dawley ◽  
Renal Nerve ◽  
Contralateral Kidney ◽  
Sprague Dawley Rats

Renal artery stenosis is increasing in prevalence. Angioplasty plus stenting has not proven to be better than medical management. There has been a reluctance to use available denervation methodologies in this condition. We studied conscious, chronically instrumented, two-kidney, one-clip (2K-1C) Goldblatt rats, a model of renovascular hypertension, to test the hypothesis that renal denervation by cryoablation (cryo-DNX) of the renal nerve to the clipped kidney decreases mean arterial pressure (MAP), plasma and tissue ANG II, and contralateral renal sympathetic nerve activity (RSNA). Five-week-old male Sprague-Dawley rats underwent sham (ShC) or right renal artery clipping (2K-1C), placement of telemetry transmitters, and pair-feeding with a 0.4% NaCl diet. After 6 wk, rats were randomly assigned to cryo-DNX or sham cryotreatment (sham DNX) of the renal nerve to the clipped kidney. MAP was elevated in 2K-1C and decreased significantly in both ShC cryo-DNX and 2K-1C cryo-DNX. Tissue norepinephrine was ∼85% lower in cryo-DNX kidneys. Plasma ANG II was higher in 2K-1C sham DNX but not in 2K-1C cryo-DNX vs ShC. Renal tissue ANG II in the clipped kidney decreased after cryo-DNX. Baseline integrated RSNA of the unclipped kidney was threefold higher in 2K-1C versus ShC and decreased in 2K-1C cryo-DNX to values similar to ShC. Maximum reflex response of RSNA to baroreceptor unloading in 2K-1C was lower after cryo-DNX. Thus, denervation by cryoablation of the renal nerve to the clipped kidney decreases not only MAP but also plasma and renal tissue ANG II levels and RSNA to the contralateral kidney in conscious, freely moving 2K-1C rats.

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