A longitudinal study of short- and long-term activity levels in male and female spontaneously hypertensive, Wistar-Kyoto, and Sprague-Dawley rats.

2003 ◽  
Vol 117 (2) ◽  
pp. 271-282 ◽  
Author(s):  
Sherry A. Ferguson ◽  
Amy M. Cada
Keyword(s):  
Longitudinal Study ◽  
Activity Levels ◽  
Sprague Dawley ◽  
Male And Female ◽  
Spontaneously Hypertensive ◽  
Sprague Dawley Rats ◽  
Short And Long Term ◽  
Wistar Kyoto

High-NaCl diets increase natriuretic and diuretic responses in salt-resistant but not salt-sensitive SHR

1991 ◽  
Vol 260 (6) ◽  
pp. F890-F897 ◽  
Author(s):  
M. S. Mozaffari ◽  
S. Jirakulsomchok ◽  
Z. H. Shao ◽  
J. M. Wyss
Keyword(s):  
Arterial Pressure ◽  
Renal Denervation ◽  
Isotonic Saline ◽  
Renal Nerves ◽  
Sprague Dawley ◽  
Volume Loading ◽  
Spontaneously Hypertensive ◽  
Volume Load ◽  
Sprague Dawley Rats ◽  
Wistar Kyoto

This study tested the hypothesis that NaCl-sensitive spontaneously hypertensive rats (SHR-S) display a defect in natriuretic and diuretic responses to acute volume loading that contributes to the rise in arterial pressure observed when the rats are fed a high-NaCl diet. Seven-week-old SHR-S and NaCl-resistant SHR rats (SHR-R) and normotensive (Wistar-Kyoto and Sprague-Dawley rats) were fed high- or basal NaCl diets. After 2.5 wk on the diets, preinstrumented conscious rats received an intravenous infusion (5% body wt; 0.5 ml/min) of isotonic saline, and urine was collected through a bladder catheter for 90 min. Control rats on the high-NaCl diet (compared with basal) excreted a significantly greater percentage of Na+ and volume load. In contrast, SHR-S on high-NaCl diet (compared with basal) had a very small increase in natriuretic response and no increase in diuretic response to volume expansion. The effect of renal denervation on natriuretic and diuretic responses to volume load was tested. In SHR-R on 1 and 8% NaCl diets, renal denervation had little or no effect on these responses, suggesting that renal nerves do not play a prominent role in the dietary NaCl-induced increases in the natriuretic and diuretic responses to volume load. These results demonstrate that NaCl-resistant rats rapidly adapt to diets high in NaCl content with increased natriuretic and diuretic responses to acute volume loading. The failure of SHR-S to adapt to the dietary challenge may result in volume loading and a secondary increase in arterial pressure after feeding.

Long-term captopril treatment restores natriuresis after carotid baroreceptor activation in the SHR

1997 ◽  
Vol 273 (1) ◽  
pp. R70-R79
Author(s):  
J. P. Valentin ◽  
S. A. Mazbar ◽  
M. H. Humphreys
Keyword(s):  
Renal Plasma Flow ◽  
Renal Nerves ◽  
Sprague Dawley ◽  
Wky Rats ◽  
Sprague Dawley Rats ◽  
Long Term Treatment ◽  
Bilateral Carotid ◽  
Wistar Kyoto ◽  
Captopril Treatment

In anesthetized Sprague-Dawley rats, intermittent bilateral carotid artery traction (BilCAT) caused a transient decrease in mean arterial pressure (MAP) of 28 +/- 3 mmHg and led to a progressive increase in sodium excretion (UNaV) that nearly doubled 45-90 min after initiation of the repetitive application of BilCAT (P < 0.001). This natriuresis was accompanied by an increase in glomerular filtration rate (GFR) from 2.70 +/- 0.3 to 3.2 +/- 0.3 ml/min (P < 0.001), no change in renal plasma flow [clearance of p-aminohippurate (PAH)], and an increase in the fractional excretion of lithium. Rats with bilateral renal denervation exhibited neither natriuresis nor an increase in GFR in response to BilCAT despite similar vasodepression caused by the maneuver. Normotensive Wistar-Kyoto (WKY) rats responded to BilCAT like Sprague-Dawley rats, whereas spontaneously hypertensive rats (SHR) exhibited an exaggerated vasodepressor response to BilCAT (-51 +/- 3 mmHg) without increasing either UNaV or GFR. Separate groups of WKY and SHR were treated from 4 wk of age with captopril added to the drinking water at a concentration of 1 g/l. At 12-14 wk, both groups had lower MAP compared with untreated animals. Captopril treatment did not alter either the natriuretic response or the increase in GFR seen in untreated WKY after BilCAT, and the maneuver produced equivalent degrees of vasodepression as in controls. However, treated SHR now responded to BilCAT with increases in both UNaV and GFR that closely resembled the responses seen in Sprague-Dawley and WKY rats. These results suggest that BilCAT produces natriuresis through a pathway dependent on the renal nerves. This pathway does not function in untreated SHR despite similar vasodepression. Long-term treatment with captopril restores this reflex pathway in SHR, lending support to the concept that angiotensin II is critically linked to heightened sympathetic nerve activity and abnormal sodium metabolism in this strain.

scholarly journals Effects of dietary salt on angiotensin peptides in kidney.

1995 ◽  
Vol 6 (4) ◽  
pp. 1209-1215
Author(s):  
Q C Meng ◽  
J Durand ◽  
Y F Chen ◽  
S Oparil
Keyword(s):  
Angiotensin Ii ◽  
Spontaneously Hypertensive Rats ◽  
Spontaneously Hypertensive Rat ◽  
Sprague Dawley ◽  
Dietary Salt ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Angiotensin Peptides ◽  
Sprague Dawley Rats ◽  
Wistar Kyoto

This study used a novel simple method for the extraction, separation, identification, and quantitation of angiotensin-like immunoactivity from tissue to examine the effects of altering dietary NaCl intake on intrarenal angiotensin I, II, and III levels in salt-sensitive, spontaneously hypertensive rats, salt-resistant Wistar-Kyoto rats, and Sprague-Dawley rats. Seven-week-old male spontaneously hypertensive rats, Wistar-Kyoto rats, and Sprague-Dawley rats were assigned randomly to a diet containing either 8% (high) or 1% (basal) salt and were maintained on these diets for 3 wk. Rats were then decapitated without prior anesthesia, and kidneys were rapidly (< 30 s) removed, snap frozen in liquid nitrogen, and stored at -80 degrees C. Frozen tissue was extracted in 2 M acetic acid and then subjected to solid-phase extraction with the cation exchange resin AG 50W X4. Angiotensin peptides were separated by reversed-phase high-performance liquid chromatography on a phenyl silica gel column with an eluent consisting of 20% acetonitrile in 0.1 M ammonium phosphate buffer, pH 4.9, and quantitated by radioimmunoassay. The elution of standard peptides under isocratic conditions revealed clear resolution of angiotensin I, II, and III and the (1-7) and (3-8) peptides. Recoveries of both labeled and unlabeled angiotensin peptide standards from the extraction step were > 90%. Renal angiotensin II stores were significantly higher in spontaneously hypertensive rats than in Wistar-Kyoto or Sprague-Dawley rats, independent of diet. Renal angiotensin II and III were further suppressed during dietary salt supplementation in both salt-resistant strains but not in the spontaneously hypertensive rat. These findings are consistent with an enhanced (compared with Wistar-Kyoto and Sprague-Dawley rats) role for angiotensin II in the kidney of the salt-sensitive, spontaneously hypertensive rat, particularly under conditions of dietary salt supplementation.

Modulation of central glucocorticoid receptors in short- and long-term experimental hypothyroidism

2015 ◽  
Author(s):  
Elena Nikolopoulou ◽  
Dimitris Mytilinaios ◽  
Dimitris Spinos ◽  
Nikitas – Apollon Panagiotopoulos ◽  
George P. Chrousos
Keyword(s):  
Glucocorticoid Receptor ◽  
Binding Affinity ◽  
Glucocorticoid Receptors ◽  
Mrna Levels ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Receptor Number ◽  
Short And Long Term

Aim: Normal adrenocortical responsiveness to stress involves glucocorticoid negative feedback to terminate hypothalamic-pituitary-adrenal (HPA) axis activation. Hypothyroidism is associated with a centrally mediated adrenal insufficiency associated. The aim of this study was to examine whether this may be explained by a disturbed glucocorticoid feedback through specific brain receptors: the mineralocorticoid (MR) and glucocorticoid receptor (GR). Methods: Cytosolic receptor binding and gene expression was assessed in male Sprague-Dawley rats (350gm) with short- (7 days) and long-standing (60 days) hypothyroidism (thyroidectomy). Glucocorticoid receptor number and binding affinity in the hippocampus were measured using radioreceptor assay. In situ hybridization was employed to examine GR and MRmRNA levels in the hippocampus and the pituitary. Results: No differences in receptor number or affinity were observed after 7days and 60days treatment. Increased GRmRNA expression in the anterior pituitary was observed in 7day hypothyroid rats under basal conditions compared to euthyroid rats (122.77+4.93 vs 99.65+4.83 DPM/mg; p<0.05), which was associated with significantly decreased GRmRNA levels after osmotic stress (100.82+2.8 vs 110.48+4.1 DPM/mg; p<0.05). No differences were observed at 60days. No effect on MR mRNA expression in the hippocampus was seen in basal condition after both 7- and 60days hypothyroidism. MRmRNA was significantly decreased in 60 days-hypothyroid rats compared to euthyroid after normal saline (3995.67+131.54 vs 5121.00+505.2 DPM/mg; p<0.05). Conclusion: Hypothyroidism resulted in significant changes in GR and MR mRNA levels, in the hippocampus and the pituitary, without changes in receptor number and binding affinity.

scholarly journals Urolithiasis in the Sprague-Dawley rat

1979 ◽  
Vol 13 (1) ◽  
pp. 17-20 ◽  
Author(s):  
Michael Paterson
Keyword(s):  
General Interest ◽  
Sprague Dawley ◽  
Sprague Dawley Rat ◽  
Sprague Dawley Rats ◽  
Short And Long Term ◽  
Long Term Studies

A 7 year collection of calculi from short- and long-term studies with Sprague-Dawley rats showed that although the incidence of rats with urolithiasis was small (0·5%), the variety of sizes and composition of the calculi could be of general interest.

Vasodepressor Effects of Arachidonic Acid and Prostacyclin (PGI2) in Hypertensive Rats

1981 ◽  
Vol 61 (s7) ◽  
pp. 315s-318s ◽  
Author(s):  
G. J. Dusting ◽  
R. Di Nicolantonio ◽  
T. Drysdale ◽  
A. E. Doyle
Keyword(s):  
Arachidonic Acid ◽  
Renal Hypertension ◽  
Sprague Dawley ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Intravenous Injections ◽  
Sprague Dawley Rats ◽  
Experimental Renal Hypertension ◽  
Wistar Kyoto ◽  
High Doses

1. Vasodepressor responses to prostacyclin and nitroprusside were compared in anaesthetized, spontaneously hypertensive rats of the Okamoto strain and Wistar—Kyoto controls, and also in one-kidney, one-clip hypertensive rats and unilaterally nephrectomized controls of the Sprague—Dawley strain. The responses, measured as a percentage of resting blood pressure, did not differ significantly between the hypertensive rats and the normotensive controls within each strain. 2. The effects of intravenous injections of arachidonic acid were also studied in each strain. 3. The vasodepressor effects of high doses of arachidonic acid (1 or 3 mg/kg) were much greater and more prolonged in both groups of hypertensive rats. These differences were abolished by indomethacin (2 mg/kg). 4. Comparisons between the strains showed that whereas Okamoto rats have significantly greater depressor responsiveness to nitroprusside and prostacyclin than Sprague—Dawley rats, the depressor effects of high doses of arachidonic acid (1 and 3 mg/kg) were smaller in the normotensive Wistar-Kyoto than in the Sprague—Dawley rats. 5. It is concluded that hypertensive rats have enhanced ability to transform exogenous arachidonic acid into vasodilator prostanoids. This occurs both in spontaneous hypertension and in experimental renal hypertension. However, rats of the Okamoto strain appear to have reduced ability to form prostacyclin when compared with Sprague—Dawley rats.

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