Determinants of High Blood Pressure in Salt-Deprived Renal Hypertensive Rats: Role of Changes in Plasma Volume, Extracellular Fluid Volume and Plasma Angiotensin II

1978 ◽  
Vol 55 (1) ◽  
pp. 81-87 ◽  
Author(s):  
A. J. Mourant
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
High Blood Pressure ◽  
Plasma Volume ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Right Atrial ◽  
Free Access ◽  
Plasma Angiotensin

1. Rats with indwelling aortic and right atrial cannulae were maintained on a sodium-free diet before and after renal arterial constriction combined with contralateral nephrectomy. Control animals underwent the same protocol except that non-constricting clips were used. 2. Plasma volumes in the salt-deprived animals were lower than previously determined values in animals with free access to sodium. After clipping plasma volume increased in the hypertensive animals. Extracellular fluid volume was increased equally in both normotensive and hypertensive animals on the second postoperative day only. 3. Before clipping and contralateral nephrectomy plasma angiotensin II values were higher than normal. After the operation angiotensin II concentrations fell to normal over a period of 14 days without significant differences between experimental and control groups. 4. It is concluded that high blood pressure after clipping may be in part maintained by increases in plasma volume. However, the results strongly suggest that other renal mechanisms are likely to be of major pathogenic importance.

Relation of saluretic and hypotensive effects of hydrochlorothiazide in the rat

1960 ◽  
Vol 198 (1) ◽  
pp. 148-152 ◽  
Author(s):  
Sydney M. Friedman ◽  
Miyoshi Nakashima ◽  
Constance L. Friedman
Keyword(s):  
Blood Pressure ◽  
Plasma Volume ◽  
Extracellular Space ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Urinary Volume ◽  
Hypertensive Rats ◽  
Inulin Space

Hydrochlorothiazide causes a marked loss of Na and of water in both fully alimented rats and in rats deprived of food and/or water. The increased urinary volume corresponds closely to the shrinkage of the extracellular fluid volume (inulin space) but the decrease in extracellular Na is not sufficient to account for the Na excretion, suggesting that Na is withdrawn from cells and perhaps bone stores as well. The fall in blood pressure in hypertensive rats is not due to simple shrinkage of the extracellular space and plasma volume, but can be referred to the rise in Na gradient induced by withdrawal of cell sodium.

Renal Control of Changes in the Compliance of the Interstitial Space: A Factor in the Aetiology of Renoprival Hypertension

1973 ◽  
Vol 44 (4) ◽  
pp. 397-416 ◽  
Author(s):  
J. Lucas ◽  
M. A. Floyer
Keyword(s):  
Blood Pressure ◽  
Plasma Volume ◽  
Venous Pressure ◽  
Extracellular Fluid ◽  
Interstitial Space ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Unilateral Nephrectomy ◽  
Interstitial Tissue ◽  
Tissue Pressure

1. Measurements of plasma volume, haematocrit, extracellular fluid volume, blood pressure, venous pressure and interstitial tissue pressure were made in rats 4 days after unilateral nephrectomy. Measurements were repeated either 4 days after subsequent removal of the remaining kidney, or 4 days after anastomosis of the remaining ureter with the inferior vena cava. Extracellular fluid volume was expanded by giving 0.5% saline by mouth: in one series blood volume was expanded by injections of blood. 2. Plasma volume (PV) rose more after bilateral nephrectomy (BN), extracellular fluid volume (ECFV) more after unilateral nephrectomy and ureterocaval anastomosis (UNUCA). The PV/ECFV ratio was significantly higher after BN. 3. Blood pressure and venous pressure rose after BN but not after UNUCA. Interstitial tissue pressure (TP) rose more after BN in spite of greater expansion of interstitial fluid volume (IFV = ECFV-PV) after UNUCA. The ratio ΔIFV/ΔTP was several times less after BN than after UNUCA. 4. Interstitial space compliance was estimated by measuring changes in IFV and TP 10 min after a saline infusion (compliance = ΔIFV/ΔTP). After UNUCA there was little change from values obtained after unilateral nephrectomy alone; following BN compliance fell severalfold. 5. It is suggested that changes in compliance of the interstitial space may be brought about by a substance secreted by the kidney and represent a hitherto undetected mechanism by which plasma volume is maintained constant under different conditions of hydration. Changes in interstitial space compliance may also play a part in the aetiology of renoprival hypertension by raising tissue pressure, and thus venous pressure and cardiac output.

scholarly journals Effects of nonsteroidal anti-inflammatory drugs on plasma volume and extracellular fluid volume in rats

1978 ◽  
Vol 28 ◽  
pp. 179
Author(s):  
Toshiaki Kadokawa ◽  
Kanno Hosoki ◽  
Kunihiko Takeyama ◽  
Hisao Minato ◽  
Masanao Shimizu
Keyword(s):  
Plasma Volume ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Inflammatory Drugs ◽  
Anti Inflammatory

Restraint vs. hindlimb suspension on fluid and electrolyte balance in rats

1996 ◽  
Vol 80 (6) ◽  
pp. 1993-2001 ◽  
Author(s):  
F. Bouzeghrane ◽  
S. Fagette ◽  
L. Somody ◽  
A. M. Allevard ◽  
C. Gharib ◽  
...  
Keyword(s):  
Plasma Volume ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Hindlimb Suspension ◽  
Sodium Thiocyanate ◽  
Electrolyte Balance ◽  
Experimental Protocol ◽  
Osmotic Load ◽  
Atrial Natriuretic

To determine the effect of hindlimb suspension on body fluid volume, salt and water balance, and relevant hormones, two series of experiments were performed in an experimental protocol including periods of isolation (7 days), horizontal attachment (7 days), and suspension (14 days). 1) During the first experiment, water and electrolyte balance, arginine vasopressin (AVP), and guanosine 3',5'- cyclic monophosphate (cGMP) were determined in urine, atrial natriuretic peptide in plasma and atria, and renin concentration and AVP in plasma in 30 rats. 2) During the second experiment, blood volume and extracellular fluid volume were measured by a dilution technique (Evans blue and sodium thiocyanate) in another 30 rats. We observed a pronounced and early effect of horizontal attachment on the renal variables. After 48 h, diuresis (49%), natriuresis (44%), kaliuresis (36%), osmotic load (39%), creatinine (28%), and AVP excretion (155%) were significantly increased in attached rats (P < 0.05). There was no short-term (24-h) effect of suspension on urine flow and Na+, K+, creatinine, and AVP excretion, but the urine cGMP decreased significantly (45%; P < 0.05). Significant decreases in natriuresis, kaliuresis, urine creatinine, and osmotic load occurred in the suspension group 7 days after suspension. After the 14-day tail suspension, plasma volume and extracellular fluid volume measured in suspended rats were not different from isolated rat values, whereas plasma volume increased by 15% (P < 0.05) in the attached rats. Plasma immunoreactive plasma atrial natriuretic levels of suspended rats were significantly reduced by 35% vs. isolated rats (P < 0.001) and by 18% vs. attached rats (P < 0.05). By using this experimental protocol, the physiological alterations revealed that suspension produced some acute and long-term effects, but the fixation to the suspension device, restraint, and confinement have their own influence on fluid distribution and renal function.

Time course and magnitude of changes in total body water, extracellular fluid volume, intracellular fluid volume and plasma volume during submaximal exercise and recovery in horses

2004 ◽  
Vol 1 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Michael I Lindinger ◽  
Gloria McKeen ◽  
Gayle L Ecker
Keyword(s):  
Plasma Volume ◽  
Total Body Water ◽  
Time Course ◽  
Extracellular Fluid ◽  
Submaximal Exercise ◽  
Body Water ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Intracellular Fluid ◽  
Total Body

AbstractThe purpose of the present study was to determine the time course and magnitude of changes in extracellular and intracellular fluid volumes in relation to changes in total body water during prolonged submaximal exercise and recovery in horses. Seven horses were physically conditioned over a 2-month period and trained to trot on a treadmill. Total body water (TBW), extracellular fluid volume (ECFV) and plasma volume (PV) were measured at rest using indicator dilution techniques (D2O, thiocyanate and Evans Blue, respectively). Changes in TBW were assessed from measures of body mass, and changes in PV and ECFV were calculated from changes in plasma protein concentration. Horses exercised by trotting on a treadmill for 75–120 min incurred a 4.2% decrease in TBW. During exercise, the entire decrease in TBW (mean±standard error: 12.8±2.0 l at end of exercise) could be attributed to the decrease in ECFV (12.0±2.4 l at end of exercise), such that there was no change in intracellular fluid volume (ICFV; 0.9±2.4 l at end of exercise). PV decreased from 22.0±0.5 l at rest to 19.8±0.3 l at end of exercise and remained depressed (18–19 l) during the first 2 h of recovery. Recovery of fluid volumes after exercise was slow, and characterized by a further transient loss of ECFV (first 30 min of recovery) and a sustained increase in ICFV (between 0.5 and 3.5 h of recovery). Recovery of fluid volumes was complete by 13 h post exercise. It is concluded that prolonged submaximal exercise in horses favours net loss of fluid from the extracellular fluid compartment.

Plasma Volume and Extracellular Fluid Volume during Long-Term Treatment with Propranolol in Essential Hypertension

1972 ◽  
Vol 43 (2) ◽  
pp. 165-170 ◽  
Author(s):  
P. Sederberg-Olsen ◽  
H. Ibsen
Keyword(s):  
Essential Hypertension ◽  
Plasma Volume ◽  
Extracellular Fluid ◽  
Term Treatment ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Long Term Treatment ◽  
Significant Change

1. In ten patients with essential hypertension treated with propranolol (320 mg daily for 4 months) plasma volume and extracellular fluid volume were determined. 2. A significant increase in extracellular fluid volume (ECFV) was found, but there was no significant change in plasma volume. 3. The genesis of the increase found in ECFV is briefly discussed.

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