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TANNIC ACID AN INHIBITOR FOR ANGIOTENSIN TYPE 1 RECEPTOR AND HYPERTENSION IN SPONTANEOUSLY HYPERTENSIVE RATS
Author(s) -
Gumaste Upendra,
Snyder Russell,
Koganti Sivaramakrishna,
Karamyan Vardan,
Thekkumkara Thomas
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.lb486
Subject(s) - angiotensin ii , blood pressure , endocrinology , medicine , tannic acid , receptor , renin–angiotensin system , kidney , angiotensin ii receptor type 1 , chemistry , mean arterial pressure , heart rate , organic chemistry
Our study in rat liver cells showed that tannic acid (TA), a polyphenol present in fruits and vegetables down‐regulates angiotensin type 1 receptor (AT1R) expression. However, in vivo effects of TA on blood pressure and AT1R expression were not known. In this study we examined the possible protective effects of TA on blood pressure, AT1R receptor protein and mRNA expression in target tissues of spontaneously hypertensive rats (SHR). Animals with a base line mean arterial pressure (MAP); 142.404 ± 9.303 mmHg were daily treated (IP) with TA (5mg/kg body weight). Treated animals showed reduced MAP (114.111 ± 2.751 mmHg) over a period of 4 weeks compared to animals treated with vehicle control (141.067 ± 7.642 mmHg). At the end of the study, withdrawal of TA treatment for a week reversed its inhibitory effects (128.344 ± 9.133 mmHg). Consistent with the reduction in blood pressure [ 3 H]Angiotensin II specific binding studies on membrane preparations showed significant reduction in AT1R receptor expression in heart and kidney with no change in the liver. However, real‐time RT‐PCR analysis showed significant reduction in AT1R mRNA expression in the liver. Furthermore, we observed AT1R blockade‐induced weight loss (9–10%) in these animals, which is consistent with the literature. These results suggest for the first time that long‐term therapy with TA can prevent hypertensive disorders in SHR. Supported by NIH Grant DK072140