title: Endothelium-independent vasorelaxant effect of puerarin on rat thoracic aorta.
abstract: To investigate the vasorelaxant effect of puerarin, tension was recorded from rat thoracic aortic rings. Puerarin completely relaxed the contractions induced by phenylephrine (PE) in a concentration-dependent manner in endothelium-intact and endothelium-denuded rat aorta, while had no effect on those preconstricted by a high concentration of potassium chloride (60 mM). Also, puerarin had no effects on the transient contraction elicited by PE or caffeine in Ca2+- free medium. The relaxant effect of puerarin was significantly inhibited by pretreatment of endothelium-denuded aorta with potassium channel antagonists tetraethylammonium and 4-aminopyridine, but not glibenclamide. These results indicate that puerarin induces an endothelium-independent relaxation in rat aortic rings. The mechanisms may involve the reduction in Ca2+ influx through the non-voltage-sensitive calcium channels and the activation of the potassium channels (voltage-activated K+ channels and large conductance Ca2+ -activated K+ channels, but not ATP-sensitive K+ channels).
authors.affiliation: Department of Cardiology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
authors.forename: K
authors.initials: K
authors.lastname: Dong
authors.forename: Q-M
authors.initials: QM
authors.lastname: Tao
authors.forename: Q-X
authors.initials: QX
authors.lastname: Shan
authors.forename: H-F
authors.initials: HF
authors.lastname: Jin
authors.forename: G-B
authors.initials: GB
authors.lastname: Pan
authors.forename: J-Z
authors.initials: JZ
authors.lastname: Chen
authors.forename: J-H
authors.initials: JH
authors.lastname: Zhu
authors.forename: Q
authors.initials: Q
authors.lastname: Xia