Details

Autor(en) / Beteiligte

• Hui-ping Wang
• Ru-huan Mei
• Xu-yun Li
• Meng-hui Zhao
• Yuan Lu
• Bruce, I.C.
• Qiang Xia

Titel

Endothelium-independent Vasorelaxant Effect of the Phyto-oestrogen Biochanin A on Rat Thoracic Aorta

Ist Teil von

• 2005 IEEE Engineering in Medicine and Biology 27th Annual Conference, 2005, Vol.2005, p.2244-2247

Ort / Verlag

United States: IEEE

Erscheinungsjahr

2005

Quelle

IEEE Electronic Library Online

Beschreibungen/Notizen

• Epidemiological data suggest that the incidence of cardiovascular disease is reduced in people who have a high intake of phytoestrogens. The plant-derived estrogen biochanin A is known to cause vasodilation, but its mechanisms of action remain unclear. This study was undertaken to investigate the effects and mechanisms of biochanin A on rat thoracic aorta. Isolated aortic rings were suspended in individual organ baths and isometric tension was measured. Biochanin A induced significant relaxation in rings with or without endothelium. Contractile responses induced by phenylephrine (PE), KCl and CaCl 2 were antagonized by 10 -7 ~10 -4 mol/L biochanin A. The transient contraction elicited by PE was significantly attenuated by 10 -5 mol/L biochanin A in Ca 2+ -free medium. The relaxant effect of biochanin A was significantly inhibited by pretreatment with the K + channel antagonists tetraethylammonium and glibenclamide in endothelium-denuded aorta. We conclude that biochanin A induces an endothelium-independent relaxation in rat aortic rings. The underlying mechanism may involve the blockage of Ca 2+ entry through both voltage-dependent and receptor-operated Ca 2+ channels, the inhibition of intracellular Ca 2+ release, and the activation of large-conductance Ca 2+ -activated K + channels and ATP-sensitive K + channels