1. Ginsenosides Rb1and Re decrease cardiac contraction in adult rat ventricular myocytes: role of nitric oxide
- Author
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Scott, Glenda I, Colligan, Peter B, Ren, Bonnie H, and Ren, Jun
- Abstract
Panax ginsengis used to enhance stamina and relieve fatigue as well as physical stress. Ginsenoside, the effective component of ginseng, regulates cardiovascular function. This study was to examine the effect of ginsenosides Rb1and Re on cardiac contractile function at the cellular level. Ventricular myocytes were isolated from adult rat hearts and were stimulated to contract at 0.5 Hz. Contractile properties analysed included: peak shortening (PS), time‐to‐90%PS (TPS), time‐to‐90% relengthening (TR90), and fluorescence intensity change (ΔFFI). Nitric oxide synthase (NOS) activity was determined by the 3H‐arginine to 3H‐citrulline conversion assay.Both Rb1and Re exhibited dose‐dependent (1 – 1000 nM) inhibition in PS and ΔFFI, with maximal inhibitions between 20 – 25%. Concurrent application Rb1and Re did not produce any additive inhibition on peak shortening amplitude (with a maximal inhibition of 24.9±6.1%), compared to Rb1or Re alone. Pretreatment with the NOS inhibitor Nω‐nitro‐L‐arginine methyl ester (L‐NAME, 100 μM) abolished the effect of Rb1and Re. Both Rb1and Re significantly (P<0.05) stimulated NOS activity concentration‐dependently.This study demonstrated a direct depressant action of ginsenosides on cardiomyocyte contraction, which may be mediated in part through increased NO production.
- Published
- 2001
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