scholarly journals Importance of local renin-angiotensin system for cardiac hypertrophy of myocardial-infarcted rats.

1993 ◽  
Vol 61 ◽  
pp. 211
Author(s):  
Shokei Kim ◽  
Hiroyuki Yamagishi ◽  
Kazuhide Takeuchi ◽  
Tadanao Takeda ◽  
Hiroshi Iwao
1999 ◽  
Vol 83 (12) ◽  
pp. 53-57 ◽  
Author(s):  
Tsutomu Yamazaki ◽  
Issei Komuro ◽  
Yoshio Yazaki

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Naoko Matsushita ◽  
Masamichi hirose ◽  
Yasuchika Taeishi ◽  
Satoshi Suzuki ◽  
Toshihide Kashihara ◽  
...  

Introduction: Transgenic mice with transient cardiac expression of constitutively active Galpha q (Gαq-TG) caused progressive heart failure and ventricular arrhythmias after the initiating stimulus becomes undetectable. However, the mechanisms are still unknown. Renin-angiotensin system plays a critical role in the development of cardiac hypertrophy and heart failure. We examined the effects of chronic administration of olmesartan on ventricular function, the number of premature ventricular contractions (PVC), and ventricular remodeling in Gαq-TG mice. Methods and Results: Olmesartan (1 mg/kg/day) or vehicle was chronically administered to Gαq-TG from 6 to 32 weeks of age, and all experiments were performed in mice at the age of 32 weeks. Chronic olmesartan treatment prevented the severe reduction of left ventricular fractional shortening and inhibited ventricular interstitial fibrosis and ventricular myocyte hypertrophy in Gαq-TG. Electrocardiogram demonstrated that premature ventricular contraction (PVC) was frequently (more than 20 beats/min) observed in 9 of 10 vehicle-treated Gαq-TG but in none of 10 olmesartan -treated Gαq-TG. The QT interval was significantly shorter in olmesartan-treated Gαq-TG than vehicle-treated Gαq-TG. CTGF, collagen type 1, ANP, BNP, and β-MHC gene expression was increased in vehicle-treated Gαq-TG. Olmesartan significantly decreased these gene expressions in Gαq-TG. Moreover, protein expressions of canonical transient receptor potential (TRPC) channels 3 and 6 increased in vehicle-treated Gαq-TG hearts. Olmesartan significantly decreased TRPC6 expressions in Gαq-TG. Angiotensin converting enzyme (ACE) 1 and 2 gene expressions were also increased in vehicle-treated Gαq-TG and was not decreased to the control level in olmesartan-treated Gαq-TG. Conclusions: These findings suggest that renin-angiotensin system has an important role in the development of cardiac hypertrophy and heart failure even if the initiating stimulus is different from the activation of renin-angiotensin system.


1999 ◽  
Vol 276 (6) ◽  
pp. H1818-H1826 ◽  
Author(s):  
Alan T. Hirsch ◽  
John A. Opsahl ◽  
Mary M. Lunzer ◽  
Stephen A. Katz

The renin-angiotensin system promotes cardiac hypertrophy after myocardial infarction. The purpose of this study was to measure renin and angiotensinogen in plasma and myocardium 10 days after myocardial infarction. Infarction involving 45 ± 4% of left ventricular circumference with accompanying hypertrophy was induced in rats ( n = 14). Plasma and myocardial renin were increased after infarction compared with sham controls ( n = 8) (27.4 ± 3.2 vs. 7.5 ± 1.8 ng ANG I ⋅ ml plasma ⋅ h−1, P < 0.0002; and 8.8 ± 1.6 vs. 2.5 ± 0.1 ng ANG I ⋅ g myocardium−1 ⋅ h−1, P < 0.008, respectively). After infarction, myocardial renin was correlated with infarct size ( r = 0.62, P < 0.02) and plasma renin ( r = 0.55, P < 0.04). Plasma angiotensinogen decreased in infarct animals, but myocardial angiotensinogen was not different from shams (1.1 ± 0.08 vs. 2.03 ± 0.06 nM/ml plasma, P < 0.002; and 0.081 ± 0.008 vs. 0.070 ± 0.004 nM/g myocardium, respectively). In conclusion, myocardial renin increased after infarction in proportion to plasma renin and infarct size, and myocardial angiotensinogen was maintained after infarction despite decreased plasma angiotensinogen and increased levels of myocardial renin.


1997 ◽  
Vol 273 (2) ◽  
pp. H593-H599 ◽  
Author(s):  
H. Kobori ◽  
A. Ichihara ◽  
H. Suzuki ◽  
T. Takenaka ◽  
Y. Miyashita ◽  
...  

This study was conducted to examine whether the renin-angiotensin system contributes to hyperthyroidism-induced cardiac hypertrophy without involving the sympathetic nervous system. Sprague-Dawley rats were divided into control-innervated, control-denervated, hyperthyroid-innervated, and hyperthyroid-denervated groups using intraperitoneal injections of thyroxine and 6-hydroxydopamine. After 8 wk, the heart-to-body weight ratio increased in hyperthyroid groups (63%), and this increase was only partially inhibited by sympathetic denervation. Radioimmunoassays and reverse transcription-polymerase chain reaction revealed increased cardiac levels of renin (33%) and angiotensin II (53%) and enhanced cardiac expression of renin mRNA (225%) in the hyperthyroid groups. These increases were unaffected by sympathetic denervation or 24-h bilateral nephrectomy. In addition, losartan and nicardipine decreased systolic blood pressure to the same extent, but only losartan caused regression of thyroxine-induced cardiac hypertrophy. These results suggest that thyroid hormone activates the cardiac renin-angiotensin system without involving the sympathetic nervous system or the circulating renin-angiotensin system; the activated renin-angiotensin system contributes to cardiac hypertrophy in hyperthyroidism.


1998 ◽  
Vol 31 ◽  
pp. S403-S405 ◽  
Author(s):  
M. Stula ◽  
Y. M. Pinto ◽  
S. Gschwend ◽  
A. C. Teisman ◽  
W. H. van Gilst ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document