[Vasodilation effect of EUL on rat thoracic artery].
OBJECTIVE
To observe vasodilation effect of EUL and its mechanism.


METHODS
Isometric tension was recorded in isolated rat thoracic artery precontracted by noradrenaline (NE) to study the vasodilation effect of EUL, and to investigate the role of endothelial cell and vascular smooth muscle cell on vasodilation.


RESULTS
EUL was shown to significantly relax the endothelium-intact arteries precontracted by NE, relaxation had fall down on endothelium-denuded arteries. EUL did not affect the concentration-contraction curve of K+. NE and CaCl2 to shift to the right with an decrease in the maximum effective response, manifesting non-competitive antagonism (P <0. 01). The relaxant effect of EUL was significantly inhibited by pretreatment of endothelium-denuded aorta with potassium channel antagonist glibenclamide.


CONCLUSIONS
EUL induces relaxation in rat aortic rings. The mechanisms may involve the endothelium and the activation of the potassium channels.
Xu
Ji-yang
JY
China Pharmaceutical University, Nanjing 210009, China. jiyangx@126.com
Song
Yan
Y
Ji
Hui
H
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D031283:Eucommiaceae / Q000737:chemistry*; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D017705:Lignans / Q000302:isolation & purification / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000302:isolation & purification / Q000494:pharmacology
D017705:Lignans; D026902:Potassium Channel Blockers; D014665:Vasodilator Agents; D005905:Glyburide; D009638:Norepinephrine