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Genistein Inhibits Sympathetic Vasomotor Tone through Nitric Oxide and Tyrosine Phosphorylation in Rostral Ventrolateral Medulla
Author(s) -
Wu YuMin,
Ma HuiJuan,
Wang Xin,
He RuiRong,
Li DePei
Publication year - 2008
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.22.1_supplement.1169.10
Subject(s) - genistein , rostral ventrolateral medulla , microinjection , medicine , endocrinology , nitric oxide , sodium orthovanadate , chemistry , nitric oxide synthase , protein tyrosine phosphatase , heart rate , receptor , blood pressure
Injection of 17β‐estradiol into the rostral ventrolateral medulla (RVLM) decreases sympathetic vasomotor tone. Phytoestrogen genistein inhibits protein tyrosine kinase and stimulates nitric oxide (NO) production. In this study, we determined the signaling transduction mechanisms underlying the sympathoinhibitory effect of genistein in the RVLM. Renal sympathetic nerve activity (RSNA), arterial blood pressure (ABP), and heart rate (HR) were recorded in urethane‐anesthetized rats. Bilateral microinjection of genistein (2, 20, and 200 pmol, 2 μl) into the RVLM dose‐dependently decreased RSNA, ABP, and HR. Pre‐microinjection of 200 pmol tamoxifen (a selective estrogen receptor antagonist) into the RVLM potentiated the inhibitory effects of genistein (20 pmol) on RSNA, BP, and HR. On the other hand, pre‐ microinjection of either 2 nmol sodium orthovanadate (an inhibitor of protein tyrosine phosphatase) or 200 pmol L‐NAME (a non‐selective nitric oxide synthesis inhibitor) into the RVLM attenuated the inhibitory effects of genistein on RSNA, BP, and HR. Furthermore, pre‐microinjection of a mixture of L‐NAME and sodium orthovanadate abolished genistein‐induced decreases in RSNA, BP, and HR. Collectively, these data provide these data provide novel information that nitric oxide and tyrosine phosphorylation are involved in the genistein‐induced sympathoinhibitory response in the RVLM.