Body Fluid Volumes in the Spontaneously Hypertensive Rat

1981 ◽  
Vol 61 (6) ◽  
pp. 685-691 ◽  
Author(s):  
M. Bianchi ◽  
G. Bellini ◽  
H. Hessan ◽  
K. E. Kim ◽  
C. Swartz ◽  
...  
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Volume ◽  
Evans Blue ◽  
Spontaneously Hypertensive Rat ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Spontaneously Hypertensive ◽  
Hypertensive Rat

1. Plasma volume, packed cell volume (PCV), blood volume, extracellular fluid volume (ECFV) and Evans blue disappearance rate were measured in conscious spontaneously hypertensive rats and in weight-matched Wistar normotensive rats. 2. Over the weight range studied (250-350 g), plasma and blood volumes were significantly lower in the spontaneously hypertensive rat. Extracellular fluid volumes were similar in the two groups. PCV arid Evans blue disappearance rates were significantly higher in the spontaneously hypertensive rat. 3. Negative correlations were obtained between plasma volume and mean arterial pressure and between the plasma/interstitial fluid volume ratio and mean arterial pressure. 4. the normal extracellular fluid volume and the lack of correlation with mean arterial pressure excludes volume expansion as a pressor mechanism during the established phase of hypertension in the spontaneously hypertensive rat.

scholarly journals High versus low ultrafiltration rates during experimental peritoneal dialysis in rats: Acute effects on plasma volume and systemic haemodynamics

2022 ◽  
pp. 089686082110692
Author(s):  
Jakob Helman ◽  
Carl M Öberg
Keyword(s):  
Peritoneal Dialysis ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Central Venous Pressure ◽  
Plasma Volume ◽  
Venous Pressure ◽  
Extracellular Fluid ◽  
Extracellular Fluid Volume ◽  
Central Venous ◽  
Plasma Compartment

Introduction: Intradialytic hypotension is a common complication of haemodialysis, but uncommon in peritoneal dialysis (PD). This may be due to lower ultrafiltration rates in PD compared to haemodialysis, allowing for sufficient refilling of the blood plasma compartment from the interstitial volume, but the underlying mechanisms are unknown. Here we assessed plasma volume and hemodynamic alterations during experimental PD with high versus low ultrafiltration rates. Methods: Experiments were conducted in two groups of healthy Sprague-Dawley rats: one group with a high ultrafiltration rate ( N = 7) induced by 8.5% glucose and a low UF group ( N = 6; 1.5% glucose), with an initial assessment of the extracellular fluid volume, followed by 30 min PD with plasma volume measurements at baseline, 5, 10, 15 and 30 min. Mean arterial pressure, central venous pressure and heart rate were continuously monitored during the experiment. Results: No significant changes over time in plasma volume, mean arterial pressure or central venous pressure were detected during the course of the experiments, despite an ultrafiltration (UF) rate of 56 mL/h/kg in the high UF group. In the high UF group, a decrease in extracellular fluid volume of −7 mL (−10.7% (95% confidence interval: −13.8% to −7.6%)) was observed, in line with the average UF volume of 8.0 mL (standard deviation: 0.5 mL). Conclusion: Despite high UF rates, we found that plasma volumes were remarkably preserved in the present experiments, indicating effective refilling of the plasma compartment from interstitial tissues. Further studies should clarify which mechanisms preserve the plasma volume during high UF rates in PD.

NO dependency of RBF and autoregulation in the spontaneously hypertensive rat

2003 ◽  
Vol 285 (1) ◽  
pp. F105-F112 ◽  
Author(s):  
Simona Racasan ◽  
Jaap A. Joles ◽  
Peter Boer ◽  
Hein A. Koomans ◽  
Branko Braam
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Lower Limit ◽  
Vascular Resistance ◽  
Spontaneously Hypertensive Rat ◽  
Renal Vascular Resistance ◽  
Renal Vasculature ◽  
Spontaneously Hypertensive ◽  
Hypertensive Rat ◽  
Renal Vascular

In the spontaneously hypertensive rat (SHR), renal blood flow (RBF) has been reported to be very dependent on nitric oxide (NO); however, autoregulation is normal, albeit shifted to higher perfusion pressures. To test the hypothesis that in the SHR NO dependency of RBF autoregulation is diminished, we investigated RBF autoregulation in anesthetized young male SHR and normotensive Wistar-Kyoto (WKY) rats before and during acute intravenous NO synthase (NOS) inhibition with Nω-nitro-l-arginine (l-NNA) and urinary excretion of nitrate plus nitrite (UNOxV) at different renal perfusion pressures (RPP). Under baseline conditions, SHR had higher mean arterial pressure (147 ± 4 mmHg) and renal vascular resistance (16 ± 1 U) than WKY (105 ± 4 mmHg and 10 ± 0.5 U, respectively, P < 0.05). RBF was similar (9.4 ± 0.5 vs. 10.3 ± 0.1 ml · min-1 · g kidney wt-1). Acute NOS blockade increased mean arterial pressure similarly, but there was significantly more reduction in RBF and hence an enhanced increase in renal vascular resistance in SHR (to 36 ± 3 vs. 17 ± 1 U in WKY, P < 0.001). The renal vasculature of SHR is thus strongly dependent on NO in maintaining basal RBF. The lower limit of autoregulation was higher in SHR than WKY in the baseline situation (85 ± 3 vs. 71 ± 2 mmHg, P < 0.05). Acute l-NNA administration did not decrease the lower limit in the SHR (to 81 ± 3 mmHg, not significant) and decreased the lower limit to 63 ± 2 mmHg ( P < 0.05) in the WKY. The degree of compensation as a measure of autoregulatory efficiency attained at spontaneous perfusion pressures was comparable in SHR vs. WKY but with a shift of the curve toward higher perfusion pressures in SHR. Acute NOS blockade only increased the degree of compensation in WKY. Remarkably, UNOxV was significantly lower at spontaneous RPP in SHR. After reduction of RPP, the observed decrease in UNOxV was significantly more pronounced in WKY than in SHR. In conclusion, the renal circulation in SHR is dependent on high levels of NO; however, the capacity to modulate NO in response to RPP-induced changes in shear stress seems to be limited.

Capillary Permeability and Extracellular Fluid Volumes in Pregnancy-Induced Hypertension

1989 ◽  
Vol 77 (6) ◽  
pp. 599-604 ◽  
Author(s):  
Mark A. Brown ◽  
Vivienne C. Zammit ◽  
Sandra A. Lowe
Keyword(s):  
Plasma Volume ◽  
Evans Blue ◽  
Capillary Permeability ◽  
Extracellular Fluid ◽  
Maternal Plasma ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Blue Dye ◽  
Pregnancy Induced Hypertension ◽  
Induced Hypertension

1. Capillary permeability was determined by the disappearance rate of Evans Blue dye from plasma in healthy non-pregnant women, normal third-trimester primigravidae and primigravidae with pregnancy-induced hypertension 2. Extracellular fluid volume was determined from the disappearance curves of injected mannitol in the same subjects and the plasma volume was measured by the Evans Blue dye dilution technique 3. In normal pregnancy capillary permeability was not altered from that of non-pregnant subjects. Although extracellular fluid volume and plasma volume were increased in normal pregnant compared with nonpregnant women, the distribution of fluid between plasma volume and interstitial fluid volume was unaltered 4. Women with established pregnancy-induced hypertension had a more rapid Evans Blue disappearance rate and a lower plasma volume than normal pregnant women, independent of the presence of proteinuria. Maternal plasma volume correlated positively and significantly with fetal birth weight in women with pregnancy-induced hypertension, emphasizing the important relationship between maternal plasma volume and fetal outcome 5. The increased capillary permeability in women with pregnancy-induced hypertension was associated with a reduction in the plasma volume/interstitial fluid volume ratio but a normal extracellular fluid volume, suggesting that the reduced plasma volume did not result from sodium loss but rather from a redistribution of the total extracellular fluid volume. These changes did not differ significantly in subgroups with and without oedema.

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
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