Salt sensitivity of renin secretion, glomerular filtration rate and blood pressure in conscious Sprague-Dawley rats

2013 ◽  
Vol 210 (2) ◽  
pp. 446-454 ◽  
Author(s):  
G. L. Isaksson ◽  
J. Stubbe ◽  
P. Lyngs Hansen ◽  
B. L. Jensen ◽  
P. Bie
1998 ◽  
Vol 84 (6) ◽  
pp. 2154-2162 ◽  
Author(s):  
Cord Sturgeon ◽  
Albert D. Sam ◽  
William R. Law

Rapid measurement of glomerular filtration rate (GFR) by an inulin single-bolus technique would be useful, but its accuracy has been questioned. We hypothesized that reported inaccuracies reflect the use of inappropriate mathematical models. GFR was measured in 14 intact and 5 unilaterally nephrectomized conscious male Sprague-Dawley rats (mean weight 368 ± 12 g) by both single-bolus (25 mg/kg) and constant-infusion techniques (0.693 mg ⋅ kg−1 ⋅ min−1). The temporal decline in plasma inulin concentration was analyzed through biexponential curve fitting, which accounted for renal inulin loss before complete vascular and interstitial mixing. We compared our mathematical model based on empirical rationale with those of other investigators whose studies suggest inaccuracy of single-bolus methods. Our mathematical model yielded GFR values by single bolus that agreed with those obtained by constant infusion [slope = 0.94 ± 0.16 (SE); y intercept = 0.23 ± 0.64; r = 0.82]. In comparison to the data obtained by constant inulin infusion, this method yielded a very small bias of −0.0041 ± 0.19 ml/min. Two previously reported models yielded unsatisfactory values (slope = 1.46 ± 0.34, y intercept = 0.47 ± 1.5, r = 0.72; and slope = 0.17 ± 1.26, y intercept = 17.15 ± 5.14, r = 0.03). The biases obtained by using these methods were −2.21 ± 0.42 and −13.90 ± 1.44 ml/min, respectively. The data indicate that when appropriate mathematical models are used, inulin clearance after single-bolus delivery can be used to measure GFR equivalent to that obtained by constant infusion of inulin. Attempts to use methods of analysis for simplicity or expediency can result in unacceptable measurements relative to the clinical range of values seen.


1997 ◽  
Vol 272 (3) ◽  
pp. F312-F318 ◽  
Author(s):  
B. Treeck ◽  
K. Aukland

The effect of the NO synthase blocker N(G)-nitro-L-arginine methyl ester (L-NAME) on glomerular filtration rate (GFR) in outer (OC), middle (MC), and inner cortex (IC) was studied in anesthetized male Sprague-Dawley rats by the aprotinin method. The filtered amount of 125I- and 131I-labeled aprotinin injected before and after L-NAME injection was measured in the same cortical tissue samples after excising the kidney. Arterial pressure increased on average by 43 mmHg, whereas renal blood flow fell by 26% after L-NAME, giving an increase in renal resistance of 92%. At constant renal arterial pressure, resistance rose by only 39%, revealing that autoregulation was responsible for about one-half of the resistance increase. Total and zonal GFR showed a small, statistically insignificant increase after L-NAME, regardless of whether the renal pressure was allowed to rise or not. The response varied considerably among animals, but in each animal the GFR varied proportionately in OC, MC, and IC. We conclude that the vasodilator tone of NO is predominantly located in postglomerular resistance vessels and is similar in the three cortical layers.


1990 ◽  
Vol 258 (1) ◽  
pp. R77-R81
Author(s):  
R. S. Zimmerman ◽  
R. W. Barbee ◽  
A. Martinez ◽  
A. A. MacPhee ◽  
N. C. Trippodo

The present study was designed to determine whether atrial appendectomy would decrease the sodium excretion associated with pressor doses of arginine vasopressin (AVP) infusion in rats by decreasing circulating levels of atrial natriuretic factor (ANF). Ten to 21 days after either sham (n = 9) or bilateral atrial appendectomy (n = 13) AVP (19 ng.kg-1.min-1) was infused for 90 min in anesthetized Sprague-Dawley rats. Atrial appendectomy decreased circulating ANF levels from 469 +/- 70 pg/ml in sham-operated animals to 259 +/- 50 pg/ml (P less than 0.05) in atrial-appendectomized animals after 90 min of AVP infusion. Despite a reduction in circulating levels of ANF, sodium excretion, potassium excretion, and urine flow increased and were not affected by bilateral atrial appendectomy. Glomerular filtration rate and mean arterial pressure significantly increased in both groups of rats. The present study supports non-ANF factors such as increases in renal perfusion pressure and/or glomerular filtration rate as potential mechanisms in AVP-induced natriuresis.


2021 ◽  
Vol 28 (2) ◽  
pp. 46-58
Author(s):  
V. V. Skibitskiy ◽  
V. Yu. Vasil’ev ◽  
A. V. Fendrikova

Background. An elevated or inadequate sensitivity to salt intake is an important mechanism for maintaining high blood pressure in patients with arterial hypertension. Chronopharmacotherapy comprises an important approach to control arterial hypertension through personalised correction of blood pressure but requires a further proof of efficacy in salt-sensitive hypertensive patients.Objectives. An assessment of six-month dynamics of diurnal and nocturnal peripheral and central blood pressure in salt-sensitive patients with arterial hypertension under chronopharmacothe­rapy.Methods. A controlled randomised trial included 86 salt-sensitive patients with arterial hypertension. Salt sensitivity was estimated with a Kharchenko’s test. All patients had circadian monitoring of the peripheral and central blood pressure and glomerular filtration rate at baseline and in a six-month follow-up. The patients were randomised into 3 cohorts. Cohort A united patients received perindopril and amlodipine in morning, cohort B — perindopril in morning, amlodipine in evening, cohort C — perindopril in evening, amlodipine in morning. Statistica 12 (StatSoftInc, USA) was used for nonparametric statistical analyses.Results. In six months of chronopharmacotherapy a target arterial pressure was registered in 87.5% patients in cohort A, 96.4 and 96.2% patients in cohorts B and C, respectively. All cohorts exhibited a declining peripheral and central blood pressure over therapy. Cohort A had a greater decline in daytime, and cohorts B and C — both diurnally and nocturnally. Cohorts B and C had more patients with an adequate nocturnal blood pressure decline. Glomerular filtration rate also elevated with perindopril or amlodipine intake before bedtime.Conclusion. The perindopril or amlodipine intake before bedtime in a combined therapy for arterial hypertension provided for a target blood pressure in the overall majority of patients, effectively reduced peripheral and central blood pressure at all time intervals, contributed to optimising the circadian blood pressure profile and increased the glomerular filtration rate.


2007 ◽  
Vol 293 (2) ◽  
pp. F506-F510 ◽  
Author(s):  
Analia Loria ◽  
Virginia Reverte ◽  
Francisco Salazar ◽  
Fara Saez ◽  
M. Teresa Llinas ◽  
...  

This study was designed to test the hypothesis that blockade of angiotensin II effects during renal development accelerates the aging-related changes in renal hemodynamics and proteinuria, and that these changes are sex dependent. It has also been examined whether the deterioration of urinary concentrating ability elicited by angiotensin II blockade is sex and/or aging dependent. Newborn Sprague-Dawley rats were treated with vehicle or an AT1 angiotensin II receptor antagonist (ARA) during the first 14 postnatal days. Blood pressure, glomerular filtration rate, proteinuria, and urinary concentrating ability in response to dehydration were examined in conscious rats at 3 and 11 mo of age. ARA treatment elicited a similar increment in blood pressure in males and females that was greater ( P < 0.05) at 11 than at 3 mo of age. Glomerular filtration rate only decreased ( P < 0.05) in 11-mo-old male ARA-treated rats (0.59 ± 0.07 vs. 0.80 ± 0.07 ml·min−1·g−1 in control group). At 3 mo of age, proteinuria increased in male (107%) but not in female ARA-treated rats. However, at 11 mo of age, proteinuria increased in both sexes, but the increment was greater ( P < 0.05) in male (244%) than in female (138%) ARA-treated rats. Renal ability to concentrate urine in response to prolonged water dehydration was only reduced in ARA-treated males. The reduction of urinary concentrating ability was accentuated by aging. Therefore, we conclude that blockade of angiotensin II effects during renal development elicits an important deterioration of cortical and medullary function that is sex and aging dependent.


2015 ◽  
Vol 31 (3) ◽  
pp. 435-441 ◽  
Author(s):  
Annelies M. C. Mavinkurve-Groothuis ◽  
Frank van de Kracht ◽  
Rik Westland ◽  
Joanna A. E. van Wijk ◽  
Jacqueline J. Loonen ◽  
...  

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