scholarly journals Renal haemodynamic and tubular actions of urotensin II in the rat

2008 ◽  
Vol 198 (3) ◽  
pp. 617-624 ◽  
Author(s):  
Alaa E S Abdel-Razik ◽  
Ellen J Forty ◽  
Richard J Balment ◽  
Nick Ashton
Keyword(s):  
Body Weight ◽  
Renal Medulla ◽  
Fractional Excretion ◽  
Haemodynamic Effects ◽  
Urotensin Ii ◽  
Sprague Dawley ◽  
Minimal Impact ◽  
Sprague Dawley Rats ◽  
Fractional Excretion Of Sodium ◽  
Excretion Rates

Urotensin II (UTS) is a potent vasoactive peptide that was originally identified in teleost fish. Mammalian orthologues of UTS and its receptor (UTSR) have been described in several species, including humans and rats. We have shown previously that bolus injections of UTS caused a decrease in urine flow and sodium excretion rates in parallel with marked reductions in renal blood flow (RBF) and glomerular filtration rate (GFR). The aim of this study was to determine the effect of UTS infusion at a dose that has minimal impact upon renal haemodynamics in order to identify a potential direct tubular action of UTS. Infusion of rat UTS (rUTS) at 0.6 pmol/min per 100 g body weight in male Sprague–Dawley rats, which had no effect on RBF and caused a 30% reduction in GFR, resulted in a significant increase in the fractional excretion of sodium (vehicle 2.3±0.6 versus rUTS 0.6 pmol 4.5±0.6%, P<0.05) and potassium. At the higher dose of 6 pmol/min per 100 g body weight, haemodynamic effects dominated the response. rUTS induced a marked reduction in RBF and GFR (vehicle 1.03±0.06 versus rUTS 6 pmol 0.31±0.05 ml/min per 100 g body weight, P<0.05) resulting in an anti-diuresis and anti-natriuresis, but no change in fractional excretion of sodium or potassium. Uts2d and Uts2r mRNA expression were greater in the renal medulla compared with the cortex. Together, these data support an inhibitory action of Uts2d on renal tubule sodium and potassium reabsorption in the rat, in addition to its previously described renal haemodynamic effects.

Enhanced renal sensitivity of the spontaneously hypertensive rat to urotensin II

2008 ◽  
Vol 295 (4) ◽  
pp. F1239-F1247 ◽  
Author(s):  
Alaa E. S. Abdel-Razik ◽  
Richard J. Balment ◽  
Nick Ashton
Keyword(s):  
Renal Function ◽  
Spontaneously Hypertensive Rat ◽  
Renal Medulla ◽  
Fractional Excretion ◽  
Urotensin Ii ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Hypertensive Rat ◽  
Fractional Excretion Of Sodium ◽  
Wistar Kyoto

Urotensin II (UII) has been implicated widely in cardiovascular disease. The mechanism(s) through which it contributes to elevated blood pressure is unknown, but its emerging role as a regulator of mammalian renal function suggests that the kidney might be involved. The aim of this study was to determine the effect of UII on renal function in the spontaneously hypertensive rat (SHR). UII infusion (6 pmol·min−1·100 g body wt−1) in anesthetized SHR and control Wistar-Kyoto (WKY) rats produced marked reductions in glomerular filtration rate (ΔGFR WKY, n = 7, −0.3 ± 0.1 vs. SHR, n = 7, −0.6 ± 0.1 ml·min−1·100 g body wt−1, P = 0.03), urine flow, and sodium excretion rates, which were greater in SHR by comparison with WKY rats. WKY rats also showed an increase in fractional excretion of sodium (ΔFENa; +0.6 ± 0.1%, P = 0.02) in contrast to SHR in which no such change was observed (ΔFENa −0.6 ± 0.2%). Blockade of the UII receptor (UT), and thus endogenous UII activity, with urantide evoked an increase in GFR which was greater in SHR (+0.3 ± 0.1) compared with WKY rats (+0.1 ± 0.1 ml·min−1·100 g body wt−1, P = 0.04) and was accompanied by a diuresis and natriuresis. UII and UT mRNA expression were greater in the renal medulla than the cortex of both strains; however, expression levels were up to threefold higher in SHR tissue. SHR are more sensitive than WKY to UII, which acts primarily to lower GFR thus favoring salt retention in this model of hypertension.

Renal interstitial hydrostatic pressure and pressure natriuresis in pregnant rats

2000 ◽  
Vol 279 (2) ◽  
pp. F353-F357 ◽  
Author(s):  
Ali A. Khraibi
Keyword(s):  
Hydrostatic Pressure ◽  
Perfusion Pressure ◽  
Fractional Excretion ◽  
Normal Pregnancy ◽  
Renal Perfusion ◽  
Sprague Dawley ◽  
Pregnant Rats ◽  
Sprague Dawley Rats ◽  
Fractional Excretion Of Sodium ◽  
Pressure Natriuresis

The objective of this study was to test the hypothesis that a decrease in renal interstitial hydrostatic pressure (RIHP) accounts for the blunted pressure natriuresis during pregnancy. RIHP was measured in nonpregnant (NP; n = 9), midterm pregnant (MP; 12–14 days after conception; n = 10), and late-term pregnant (LP; 18–21 days after conception; n = 12) female Sprague-Dawley rats at two renal perfusion pressure (RPP) levels (99 and 120 mmHg). At the lower RPP level, RIHP was 5.9 ± 0.3 mmHg for NP, 3.4 ± 0.4 mmHg for MP ( P < 0.05 vs. NP), and 2.9 ± 0.1 mmHg for LP ( P < 0.05 vs. NP) rats. The increase in RPP from 99 to 120 mmHg resulted in pressure natriuretic and diuretic responses in all groups; however, the increases in fractional excretion of sodium (ΔFENa), urine flow rate (ΔV), and ΔRIHP were significantly greater ( P < 0.05) in NP compared with both MP and LP rats. ΔFENa, ΔV, and ΔRIHP were 2.06 ± 0.28%, 81.44 ± 14.10 μl/min, and 3.0 ± 0.5 mmHg for NP; 0.67 ± 0.13%, 28.03 ± 5.28 μl/min, and 0.5 ± 0.2 mmHg for MP; and 0.48 ± 0.12%, 18.14 ± 4.70 μl/min, and 0.4 ± 0.1 mmHg for LP rats. In conclusion, RIHP is significantly lower in pregnant compared with nonpregnant rats at similar RPP levels. Also, the ability of pregnant rats to increase RIHP in response to an increase in RPP is blunted. These changes in RIHP may play an important role in the blunted pressure natriuresis and contribute to the conservation of sodium and water that is critical for fetal growth and development during normal pregnancy.

Role of renal interstitial hydrostatic pressure in natriuresis of systemic nitric oxide inhibition

1993 ◽  
Vol 264 (3) ◽  
pp. F411-F414 ◽  
Author(s):  
J. A. Haas ◽  
A. A. Khraibi ◽  
M. A. Perrella ◽  
F. G. Knox
Keyword(s):  
Nitric Oxide ◽  
Hydrostatic Pressure ◽  
Fractional Excretion ◽  
Urinary Sodium Excretion ◽  
Renal Perfusion ◽  
Significant Rise ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Suprarenal Aorta ◽  
Fractional Excretion Of Sodium

Systemic inhibition of nitric oxide synthesis with NG-monomethyl-L-arginine (L-NMMA) increases renal perfusion pressure (RPP) and urinary sodium excretion. Increased RPP has been proposed as one of the mechanisms for the natriuresis caused by intravenous infusion of L-NMMA. We tested the hypothesis that increases in renal interstitial hydrostatic pressure (RIHP) are required for the natriuresis of L-NMMA infusion. Experiments were performed in four groups of Sprague-Dawley rats in which partial aortic clamping and/or bilateral renal decapsulation was performed to control RPP and RIHP. Infusion of L-NMMA (15 mg/kg bolus + 500 micrograms.kg-1 x min-1 continuous infusion) increased RPP (delta+ 14 +/- 1 mmHg), RIHP (delta+ 3.6 +/- 0.7 mmHg), and fractional excretion of sodium (FENa; delta 2.4 +/- 0.6%, P < 0.005). When RPP was prevented from increasing by controlling RPP with an adjustable clamp around the suprarenal aorta, RIHP and FENa did not significantly change. When only RIHP was held constant by bilateral renal decapsulation, FENa was not significantly increased (delta+ 0.68 +/- 0.36%, not significant), despite a significant rise in RPP (delta+ 18 +/- 2 mmHg, P < 0.001). Control of both RPP and RIHP prevented the increase in FENa. Thus, when renal interstitial pressure was controlled, the infusion of L-NMMA did not result in an increase in FENa. These results demonstrate that an increase in RIHP is a necessary component in the natriuresis due to systemic infusion of L-NMMA.

ANF secretion and renal responses to volume expansion with equilibrated blood

1988 ◽  
Vol 255 (5) ◽  
pp. F936-F943 ◽  
Author(s):  
R. V. Paul ◽  
T. Ferguson ◽  
L. G. Navar
Keyword(s):  
Blood Volume ◽  
Sodium Excretion ◽  
Volume Expansion ◽  
Fractional Excretion ◽  
High Dose ◽  
Sprague Dawley ◽  
Blood Volume Expansion ◽  
Step Procedure ◽  
Sprague Dawley Rats ◽  
Fractional Excretion Of Sodium

To evaluate the role of atrial natriuretic factor (ANF) in the renal response to acute blood volume expansion without hemodilution, a reservoir syringe filled with donor rat blood was connected to the femoral artery and vein of anesthetized Sprague-Dawley rats to allow rapid equilibration of the reservoir with the intravascular blood. Volume expansion with blood from the reservoir in two steps (of 1 and 1.5% body wt, separated by 1 h, n = 5 rats) produced a mean peak increase in plasma immunoreactive ANF from 99 +/- 21 to 1,310 +/- 230 pg/ml (P less than 0.001); plasma ANF levels throughout these experiments correlated significantly with simultaneously measured urine flow (r = 0.74, P less than 0.005) and sodium excretion (r = 0.65, P less than 0.005). Another group (n = 7) underwent the same two-step procedure; after the second volume expansion, high-dose atriopeptin III infusion (0.4 microgram.kg-1.min-1 did not further increase fractional excretion of sodium (3.17 +/- 0.27 to 2.50 + 0.39%, P = NS). In another group (n = 9 rats), the same dose of atriopeptin III was started before any blood volume expansion. After the resulting hypotension was corrected by restoration of blood volume, an additional 1.5% body weight blood volume expansion did not further augment sodium excretion. We conclude that the diuresis and natriuresis, which occur in response to volume expansion without hemodilution, rise and fall in parallel with immunoreactive ANF in the plasma, and that ANF and acute blood volume expansion act on the kidney through a similar, saturable mechanism.

Renoprotective effects of nitric oxide in angiotensin II-induced hypertension in the rat

1998 ◽  
Vol 274 (5) ◽  
pp. F876-F882 ◽  
Author(s):  
So Yeon Chin ◽  
Chi-Tarng Wang ◽  
Dewan S. A. Majid ◽  
L. Gabriel Navar
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Fractional Excretion ◽  
Urinary Sodium Excretion ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Hypertensive Rats ◽  
Absolute Increase ◽  
Sprague Dawley Rats ◽  
Fractional Excretion Of Sodium

Experiments were performed in anesthetized male Sprague-Dawley rats to determine whether increased nitric oxide (NO) activity during the development of hypertension exerts a protective effect on renal cortical blood flow (CBF) and medullary blood flow (MBF). The effects of acute NO synthase inhibition on renal function and on CBF and MBF, measured by laser-Doppler flow probes, were evaluated in control and ANG II-infused hypertensive rats, prepared by the infusion of ANG II at a rate of 65 ng/min via osmotic minipumps implanted subcutaneously for 13 days. In normotensive rats ( n = 8), intravenous infusion of N ω-nitro-l-arginine (NLA; 20 μg ⋅ 100 g−1 ⋅ min−1) decreased CBF by 21 ± 4% and MBF by 49 ± 8% and increased blood pressure from 118 ± 1 to 140 ± 2 mmHg. In ANG II-infused rats ( n = 7), CBF and MBF decreased by 46 ± 5% and 25 ± 6%, respectively, during infusion of NLA. Arterial pressure increased from 160 ± 5 to 197 ± 7 mmHg, which was a greater absolute increase than in normotensive controls. Basal renal blood flow (RBF), estimated from p-aminohippurate clearance and hematocrit, was similar in both the control (6.0 ± 0.5 ml ⋅ min−1 ⋅ g−1) and hypertensive (6.0 ± 0.6 ml ⋅ min−1 ⋅ g−1) rats. However, NLA-induced reductions in RBF averaged 60 ± 5% in the hypertensive rats, compared with 31 ± 9% observed in control rats. GFR in control (0.97 ± 0.03 ml ⋅ min−1 ⋅ g−1) and hypertensive rats (0.78 ± 0.12 ml ⋅ min−1 ⋅ g−1) decreased to a similar extent during the first 30-min period of NLA infusion. GFR returned toward control levels in control rats; in contrast, GFR remained significantly decreased in the ANG II-infused rats (0.58 ± 0.11 ml ⋅ min−1 ⋅ g−1). Basal urinary sodium excretion (0.2 ± 0.08 μeq ⋅ min−1 ⋅ g−1), fractional excretion of sodium (0.3 ± 0.13%), and urine flow (4.9 ± 0.39 μl ⋅ min−1 ⋅ g−1) in hypertensive rats did not increase significantly after NLA treatment as occurred in normotensive controls. These data suggest that a compensatory increase in nitric oxide activity partially counteracts the vasoconstrictor influence of elevated ANG II levels to regulate renal hemodynamics and maintain cortical perfusion in the renal circulation.

Chronic intravenous administration of V1 arginine vasopressin agonist results in sustained hypertension

1994 ◽  
Vol 267 (2) ◽  
pp. H751-H756 ◽  
Author(s):  
A. W. Cowley ◽  
E. Szczepanska-Sadowska ◽  
K. Stepniakowski ◽  
D. Mattson
Keyword(s):  
Body Weight ◽  
Arginine Vasopressin ◽  
Plasma Catecholamines ◽  
Plasma Osmolality ◽  
Sprague Dawley ◽  
Prolonged Administration ◽  
Chronic Stimulation ◽  
Sustained Hypertension ◽  
Sprague Dawley Rats

Despite the well-recognized vasoconstrictor and fluid-retaining actions of vasopressin, prolonged administration of arginine vasopressin (AVP) to normal animals or humans fails to produce sustained hypertension. The present study was performed to elucidate the role of the V1 receptor in determining the ability of AVP to produce sustained hypertension. Conscious Sprague-Dawley rats with implanted catheters were infused with the selective V1 agonist, [Phe2,Ile3,Orn8]vasopressin (2 ng.kg-1.min-1), for 14 days in amounts that were acutely nonpressor. Blood pressure (MAP), heart rate (HR), body weight, and water intake (WI) were determined daily. Plasma AVP, plasma catecholamines norepinephrine and epinephrine, plasma osmolality, and electrolyte concentration were determined before and on days 1 and 7 of infusion. MAP increased significantly by 10.4 +/- 4.5 mmHg on day 1 and rose to 22 +/- 5 mmHg above control by day 14 (transient decrease on days 6-9) and then fell to control levels after the infusion was stopped. HR did not change significantly. Plasma AVP immunoreactivity increased from 2.5 +/- 0.3 to 10.9 +/- 2.1 pg/ml, whereas norepinephrine tended to fall only on day 1, with epinephrine only slightly elevated on day 7. No evidence of fluid retention was found, and rats lost sodium only on the first day of V1 agonist infusion. Body weight increased throughout the study but was unrelated to the changes of MAP. We conclude that chronic stimulation of V1 receptors results in sustained hypertension in rats.

Defense of differfing body weight set points in diet-induced obese and resistant rats

1998 ◽  
Vol 274 (2) ◽  
pp. R412-R419 ◽  
Author(s):  
Barry E. Levin ◽  
Richard E. Keesey
Keyword(s):  
Body Weight ◽  
Diet Composition ◽  
Energy Homeostasis ◽  
Energy Content ◽  
Sprague Dawley ◽  
Fat Pad ◽  
Insulin Levels ◽  
Diet Induced Obesity ◽  
Sprague Dawley Rats ◽  
Plasma Leptin

Among outbred Sprague-Dawley rats, approximately one-half develop diet-induced obesity (DIO) and one-half are diet resistant (DR) on a diet relatively high in fat and energy content (HE diet). Here we examined the defense of body weight in these two phenotypes. After HE diet for 13 wk, followed by chow for 6 wk, DR rats gained weight comparably but their plasma leptin levels fell to 54% of chow-fed controls. When a palatable liquid diet (Ensure) was added for 13 wk, other DR rats became obese. But when switched to chow, their intakes fell by 60%, and body and retroperitoneal (RP) fat pad weights and plasma leptin and insulin levels all declined for 2 wk and then stabilized at control levels after 6 wk. In contrast, comparably obese DIO rats decreased their intake by only 20%, and their weights plateaued when they were switched to chow after 13 wk on HE diet. When a subgroup of these DIO rats was restricted to 60% of prior intake, their weights fell to chow-fed control levels over 2 wk. But their leptin and insulin levels both fell disproportionately to 30% of controls. When no longer restricted, their intake and feed efficiency rose immediately, and their body and RP pad weights and leptin and insulin levels rose to those of unrestricted DIO rats within 2 wk. Thus diet and genetic background interact to establish high (DIO) or low (DR) body weight set points, which are then defended against subsequent changes in diet composition and/or energy availability. If leptin affects energy homeostasis, it does so differentially in DIO vs. DR rats since comparably low and high levels were associated with differing patterns of weight change between the two phenotypes.

scholarly journals Antiobesity Activity of Elateriospermum tapos Shell Extract in Obesity-Induced Sprague Dawley Rats

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 321
Author(s):  
Kokila Vani Perumal ◽  
Nor Liyana Ja’afar ◽  
Che Norma Mat Taib ◽  
Nurul Husna Shafie ◽  
Hasnah Bahari
Keyword(s):  
Body Weight ◽  
Corn Starch ◽  
Milk Powder ◽  
Caloric Intake ◽  
Lipid Lowering ◽  
Sprague Dawley ◽  
Triglyceride Accumulation ◽  
Sprague Dawley Rats ◽  
Effective Result ◽  
Lipid Lowering Effect

Obesity is one of the risk factors associated with cardiovascular diseases, hypertension, abnormal liver function, diabetes, and cancers. Orlistat is currently available to treat obesity, but it is associated with adverse side effects. Natural resources are widely used for obesity treatment. Hence, this study aimed to investigate the anti-obesity activity of Elateriospermum tapos (E. tapos) shell extract in obesity induced Sprague Dawley rats. The rats’ obesity was induced by a high-fat (HF) diet made up of 50% standard rat pellet, 20% milk powder, 6% corn starch, and 24% ghee and a cafeteria (CAF) diet such as chicken rolls, salty biscuits, cakes, and cheese snacks. A hot aqueous method for the extraction of E. tapos shells was applied by using 500 mL of distilled water for about 24 h. Various dosages of E. tapos shell extract (10 mg/kg, 100 mg/kg, and 200 mg/kg) were used. At the end of the study, body weight, caloric intake, organ weight, lipid profile, lipoprotein lipase (LPL) activity, and histopathology analysis were carried out. E. tapos shell extract treated groups showed a reduction in body weight, positive lipid-lowering effect, decrements in triglyceride accumulation and LPL activity, and positive improvement in histopathology analysis. A dose of 200 mg/kg showed the most effective result compared to 10 mg/kg and 100 mg/kg doses.

The prophylactic potential of Zingiber officinale flowers and leaves extract to mitigate hyperglycemia in Sprague Dawley rats

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Saira Tanweer ◽  
Tariq Mehmood ◽  
Saadia Zainab ◽  
Zulfiqar Ahmad ◽  
Muhammad Ammar Khan ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Weight Gain ◽  
Body Weight Gain ◽  
Zingiber Officinale ◽  
Sprague Dawley ◽  
Content Type ◽  
Sprague Dawley Rats ◽  
Hematological Analysis ◽  
Therapeutic Tools

Purpose Innovative health-promoting approaches of the era have verified phytoceutics as one of the prime therapeutic tools to alleviate numerous health-related ailments. The purpose of this paper is to probe the nutraceutic potential of ginger flowers and leaves against hyperglycemia. Design/methodology/approach The aqueous extracts of ginger flowers and leaves were observed on Sprague Dawley rats for 8 weeks. Two parallel studies were carried out based on dietary regimes: control and hyperglycemic diets. At the end of the experimental modus, the overnight fed rats were killed to determine the concentration of glucose and insulin in serum. The insulin resistance and insulin secretions were also calculated by formulae by considering fasting glucose and fasting insulin concentrations. Furthermore, the feed and drink intakes, body weight gain and hematological analysis were also carried out. Findings In streptozotocin-induced hyperglycemic rats, the ginger flowers extract depicted 5.62% reduction; however, ginger leaves extract reduced the glucose concentration up to 7.11% (p = 0.001). Similarly, ginger flowers extract uplifted the insulin concentration up to 3.07%, while, by ginger leaves extract, the insulin value increased to 4.11% (p = 0.002). For the insulin resistance, the ginger flower showed 5.32% decrease; however, the insulin resistance was reduced to 6.48% by ginger leaves (p = 0.014). Moreover, the insulin secretion increased to 18.9% by flower extract and 21.8% by ginger leave extract (p = 0.001). The feed intake and body weight gain increased momentously by the addition of ginger flowers and leaves; however, the drink intake and hematological analysis remained non-significant by the addition of ginger parts. Originality/value Conclusively, it was revealed that leaves have more hypoglycemic potential as compared to flowers.

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