[Endothelium-independent vasorelaxant effect of Taurine on rat aorta rings].
OBJECTIVE
To investigate the vasorelaxant effect of taurine (Tau) in rat aortic rings and the mechanism.


METHODS
The isolated thoracic aortic rings of male Wistar rats were mounted on the organ bath. The effect of Tau 10, 20, 40, 80 mmol x L(-1) on the rings with endothelium intact or endothelium denuded precontracted by the phenylephrine (1 micromol x L(-1)) or KCl (60 mmol x L(-1)), and the effect of Tau on the vessel reaction induced by various drugs were recorded with biological signal analytical system.


RESULTS
Taurine completely relaxed the contractions induced by KCl and phenylephrine in a concentration-dependent manner in endothelium-intact and endothelium-denuded rat aorta. Taurine attenuated the contraction to PE both in the absence and presence of calcium, but had no significant effect on the contraction induced by caffeine. The relaxant effect of taurine was significantly inhibited by pretreatment of endothelium-denuded aorta with potassium channel antagonists glibenclamide and tetraethylamine but not by BaCl2 or 4-aminopyridine.


CONCLUSIONS
Taurine induces an endothelium-independent relaxation in rat aortic rings. The mechanisms may involve the reduction in Ca2+-influx and Ca2+-release and the participation of the potassium channels (KATP and KCa, but not Kir or KV).
Li
Zhidong
Z
Shanxi Medical University, Department of Pharmacology, Taiyuan, 030001, China. lee2991@163.com
Zhang
Mingsheng
M
Liang
Yueqin
Y
D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D008297:Male; D023421:Models, Animal; D009126:Muscle Relaxation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013654:Taurine / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D013654:Taurine