[Endothelium-independent vasorelaxant effect of puerarin on rat thoracic aorta].
OBJECTIVE
To investigate the vasorelaxant effect of puerarin in rat aortic rings and the mechanism.


METHODS
The isolated thoracic aortic rings of male Sprague-Dawley rats were mounted on the organ bath and the contractile responses of the vessel were recorded.


RESULTS
Puerarin completely relaxed the contractions induced by phenylephrine in a concentration-dependent manner in endothelium-intact and endothelium-denuded rat aorta, but it had no effect on those preconstricted by a high concentration of potassium chloride (KCl, 60 mmol x L(-1)). The relaxant effect of puerarin was significantly inhibited by pretreatment of endothelium-denuded aorta with potassium channel antagonists tetraethylammonium, 4-aminopyridine but not glibenclamide.


CONCLUSIONS
Puerarin induces an endothelium-independent relaxation in rat aortic rings. The mechanisms may involve the reduction in Ca2+ influx through the calcium channels operated by alpha-adrenergic receptor and the activation of the potassium channels (Kv and BKca, but not KATP).
Dong
Kan
K
Department of Cardiovascular, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China. dongkan76@sohu.com
Tao
Qian-min
QM
Xia
Qiang
Q
Shan
Qi-xian
QX
Pan
Guo-biao
GB
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D004730:Endothelium, Vascular / Q000502:physiology*; D066298:In Vitro Techniques; D007529:Isoflavones / Q000302:isolation & purification / Q000494:pharmacology*; D008297:Male; D010656:Phenylephrine / Q000037:antagonists & inhibitors; D010946:Plants, Medicinal / Q000737:chemistry; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects; D029908:Pueraria / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D019789:Tetraethylammonium / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D007529:Isoflavones; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D014665:Vasodilator Agents; D010656:Phenylephrine; D019789:Tetraethylammonium; D015761:4-Aminopyridine; C033607:puerarin