scholarly journals Protective Role of Angiotensin II Subtype 2 Receptor in Blood Pressure Increase in Obese Zucker Rats

Hypertension ◽  
2009 ◽  
Vol 53 (2) ◽  
pp. 256-261 ◽  
Author(s):  
Athar H. Siddiqui ◽  
Quaisar Ali ◽  
Tahir Hussain
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Protective Role ◽  
Pressure Increase ◽  
Zucker Rats ◽  
Blood Pressure Increase ◽  
Obese Zucker Rats

scholarly journals Blood pressure response to angiotensin II is enhanced in obese Zucker rats and is attributed to an aldosterone-dependent mechanism

2012 ◽  
Vol 166 (8) ◽  
pp. 2417-2429 ◽  
Author(s):  
Helge Müller-Fielitz ◽  
Margot Lau ◽  
Olaf Jöhren ◽  
Florian Stellmacher ◽  
Markus Schwaninger ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Blood Pressure Response ◽  
Pressure Response ◽  
Zucker Rats ◽  
Obese Zucker Rats ◽  
Dependent Mechanism

scholarly journals Reduction of renal dopamine receptor expression in obese Zucker rats: role of sex and angiotensin II

2010 ◽  
Vol 299 (5) ◽  
pp. F1164-F1170 ◽  
Author(s):  
Xiaoyan Wang ◽  
Fengmin Li ◽  
Pedro A. Jose ◽  
Carolyn M. Ecelbarger
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Receptor Expression ◽  
Female Rats ◽  
Male Rats ◽  
Zucker Rats ◽  
Protein Levels ◽  
Obese Rats ◽  
Obese Zucker Rats

Dopamine produced by renal proximal tubules increases sodium excretion via a decrease in renal sodium reabsorption. Dopamine natriuresis is impaired in obese Zucker rats; however, the mechanism is not fully understood. To test the hypothesis that renal expression of one or more of the subtypes are altered in these rats, we measured whole kidney protein levels by immunoblotting of D1-like (D1R and D5R) and D2-like (D2R, D3R, and D4R) dopamine receptors in both male and female obese and lean Zucker rats. In obese males on 1% NaCl diet, D1R, D2R, D4R, and D5R were decreased, while D3R was increased, relative to lean rats. Under a 4% NaCl diet, D2R and D3R levels in obese rats were restored to lean levels. 4% NaCl diet reduced D5R in both body types, relative to 1% NaCl diet. Female rats had higher expression of D1R and D3R than did male; however, the sex difference for D1R was markedly blunted in obese rats. In obese rats, dietary candesartan (angiotensin II type 1 receptor blocker) normalized downregulated D1R and D2R, but either decreased (D3R), did not affect (D4R), or further downregulated (D5R) the other subtypes. Candesartan also decreased D4R in lean rats. In summary, reduced renal protein levels of D1R, D2R, D4R, and D5R in obese Zucker rats could induce salt sensitivity and elevate blood pressure. Increased angiotensin II type 1 receptor activity may be mechanistically involved in the decreased expression of D1R and D2R in obese rats. Finally, reduced D1R and D3R in male rats may contribute to sex differences in blood pressure.

scholarly journals Impact of Mineralocorticoid Receptor And Angiotensin Ii Type 1 Receptor Antagonism on Blood Pressure Regulation in Obese Zucker Rats: Role of Sex Differences

2020 ◽  
Author(s):  
Jussara M do Carmo ◽  
Alexandre A da Silva ◽  
John E Hall
Keyword(s):  
Blood Pressure ◽  
Sex Differences ◽  
Mineralocorticoid Receptor ◽  
Combined Treatment ◽  
Zucker Rats ◽  
Male And Female ◽  
Obese Zucker Rats ◽  
Males And Females

Abstract Background Previous studies suggest that obesity-induced hypertension in females, but not males, is due to leptin-mediated stimulation of aldosterone secretion and subsequent activation of the mineralocorticoid receptor (MR). Although angiotensin II type 1 receptor (AT1R) antagonism lowers blood pressure (BP) in male obese Zucker rats (OZR), which have defective leptin signaling, the potential role of sex differences in BP responses to RAAS blockade, including MR antagonism, in obesity is still unclear. We tested the cardiovascular effects of MR antagonism, alone or in combination with AT1R blockade in male and female OZR (n=5/sex) and lean Zucker rats (LZR, n=7/sex). Methods BP and heart rate (HR) were measured by telemetry 24-hrs/day. After a 6-day control period, spironolactone (40 mg/kg/day) was given for 10 days followed by a 7-day combined treatment with losartan (20 mg/kg/day), and followed by 6-day post-treatment recovery period. Results Compared to lean rats, OZR were hypertensive (Mean arterial pressure: 115±4 vs. 104±2 and 111±s vs. 100±3 mmHg for males and females) and had lower HR (355±9 vs. 393±7 and 367±10 vs. 412±13 bpm). MR blockade alone did not alter BP or HR in lean or obese male and female Zucker rats, whereas combined treatment reduced BP in obese and lean rats by 31±3 vs. 21±1 and 8±1 vs. 5±1 mmHg in males and females, respectively. No changes were observed in HR. Conclusions These results suggest that there are important sex differences in BP responses to chronic AT1R blockade but no major involvement of MR activation in BP regulation in OZR.

scholarly journals The angiotensin II receptor antagonist losartan reduces blood pressure but not renal injury in obese Zucker rats.

1995 ◽  
Vol 6 (4) ◽  
pp. 1295-1299
Author(s):  
G S Crary ◽  
S K Swan ◽  
M P O'Donnell ◽  
B L Kasiske ◽  
S A Katz ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Renal Disease ◽  
Renal Injury ◽  
Zucker Rats ◽  
Angiotensin Ii Receptor ◽  
Tubulointerstitial Injury ◽  
Angiotensin Ii Receptor Antagonist ◽  
Obese Zucker Rats ◽  
Intrarenal Ras

Agents that interfere with the renin-angiotensin system (RAS) may ameliorate progressive renal injury, particularly in a setting where intrarenal RAS activity appears to be elevated. Whether RAS antagonists affect renal disease progression when intrarenal RAS activity is not increased is unclear. In this study, therefore, the effects of the angiotensin II receptor antagonist losartan on glomerular and tubulointerstitial injury were investigated in obese Zucker rats (OZR), an experimental model of progressive renal disease characterized by reduced intrarenal renin content and reduced plasma renin activity. Losartan (100 or 200 mg/L of drinking water) was administered to OZR beginning at 26 wk of age, when renal disease was established. At 38 and 44 wk of age, losartan-treated OZR demonstrated significant (P < 0.05) dose-related decreases in systolic blood pressure, compared with blood pressures in untreated, control OZR. Despite the reductions in blood pressure, losartan had no significant effects on albuminuria or glomerular or tubulointerstitial injury. At 44 wk of age, the percentage (mean +/- SE) of glomeruli with sclerosis was 51 +/- 11, 49 +/- 9, and 39 +/- 14% in control OZR, low-dose (100 mg/L) losartan-treated OZR, and high-dose (200 mg/L) losartan-treated OZR, respectively (P > 0.05). Similarly, the tubulointerstitial injury score (range, 0 to 4) in the three groups was, respectively, 1.7 +/- 0.4, 1.6 +/- 0.3, and 1.5 +/- 0.3 (P > 0.05). It was concluded that in a setting of chronic renal failure where intrarenal RAS activity does not appear to be increased, angiotensin II receptor antagonism may not be nephroprotective despite a reduction in blood pressure.

Cardiovascular protective role of a low-dose antihypertensive combination in obese Zucker rats

2003 ◽  
Vol 21 (3) ◽  
pp. 611-620 ◽  
Author(s):  
Jorge E Toblli ◽  
Graciela DeRosa ◽  
Carlos Rivas ◽  
Gabriel Cao ◽  
Pablo Piorno ◽  
...  
Keyword(s):  
Low Dose ◽  
Protective Role ◽  
Zucker Rats ◽  
Obese Zucker Rats

scholarly journals Exercise Training Restores Cardiac MicroRNA-1 and MicroRNA-29c to Nonpathological Levels in Obese Rats

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
André C. Silveira ◽  
Tiago Fernandes ◽  
Úrsula P. R. Soci ◽  
João L. P. Gomes ◽  
Diego L. Barretti ◽  
...  
Keyword(s):  
Exercise Training ◽  
Cardiac Remodeling ◽  
Target Genes ◽  
Protective Role ◽  
Aerobic Exercise Training ◽  
Heart Weight ◽  
Zucker Rats ◽  
Obese Rats ◽  
Obese Zucker Rats

We previously reported that aerobic exercise training (AET) consisted of 10 weeks of 60-min swimming sessions, and 5 days/week AET counteracts CH in obesity. Here, we evaluated the role of microRNAs and their target genes that are involved in heart collagen deposition and calcium signaling, as well as the cardiac remodeling induced by AET in obese Zucker rats. Among the four experimental Zucker groups: control lean rats (LZR), control obese rats (OZR), trained lean rats (LZR + TR), and trained obese rats (OZR + TR), heart weight was greater in the OZR than in the LZR group due to increased cardiac intramuscular fat and collagen. AET seems to exert a protective role in normalizing the heart weight in the OZR + TR group. Cardiac microRNA-29c expression was decreased in OZR compared with the LZR group, paralleled by an increase in the collagen volumetric fraction (CVF). MicroRNA-1 expression was upregulated while the expression of its target gene NCX1 was decreased in OZR compared with the LZR group. Interestingly, AET restored cardiac microRNA-1 to nonpathological levels in the OZR-TR group. Our findings suggest that AET could be used as a nonpharmacological therapy for the reversal of pathological cardiac remodeling and cardiac dysfunction in obesity.

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