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Tannic Acid Specific Inhibition of Angiotensin Type 1 Receptor in Rat Liver Epithelial Cells
Author(s) -
Yesudas Rekha,
Biju Prabath,
Thekkumkara Thomas
Publication year - 2009
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.23.1_supplement.1026.5
Subject(s) - tannic acid , mapk/erk pathway , angiotensin ii , phosphorylation , renin–angiotensin system , receptor , chemistry , polyphenol , kinase , biochemistry , protein kinase a , pharmacology , endocrinology , microbiology and biotechnology , medicine , biology , antioxidant , organic chemistry , blood pressure
Previous studies have shown that plant‐derived polyphenols appear to provide protection from hypertension. However, the target or mechanism of protective effects of polyphenols remains unclear. In the present study, we investigated the effects of tannic acid on angiotensin type 1 receptor (AT1R) expression. Exposure of rat liver epithelial cells to tannic acid resulted in significant down‐regulation of [ 3 H]angiotensin II specific binding (81432±1981 to 40399±1952 dpm/mg protein) and AT1R protein (55%) and mRNA (60%) expression in a concentration and time dependent manner. The inhibitory effect of tannic acid on AT1R was specific and reversible. Under similar conditions, we observed increased phosphorylation of both MAP‐kinases (MAPK) p42 & p44. Pretreatment of cells with MAPK specific inhibitor prevented tannic acid induced MAPK phosphorylation and down regulation of the AT1R suggesting that the observed inhibitory effect is mediated through MAPK signaling intermediate(s). Our studies demonstrate for the first time that tannic acid inhibits the AT1R gene expression and illustrate that dietary polyphenols blunt hypertension, in part through inhibition of AT1R. Supported by NIH Grant DK072140