[Effects of resveratrol on isolated thoracic aorta rings of rats].
OBJECTIVE
To investigate the relaxative characteristics of resveratrol on thoracic aortic artery in the rat and its mechanism.


METHODS
We perfused the isolated rings and observed the response of NA-induced artery contraction to resveratrol under the Ca2+-contained and Ca2+-free bath solutions. In the same way were the effect of reveratrol on the vascular smooth muscle observed by adding two different concentration of KCl (30 and 80 mmol x L(-1)), and the effect on the contraction of the vascular smooth muscle depending on the intracellular calcium and extracellular calcium were also observed by adding NA. We also observed the effect of resveratrol on the contraction of rings induced by NA in the presence of L-NNA and Glibenclamide.


RESULTS
Resveratrol relaxed rat aorta rings precontracted by NA in a dose-dependent manner. The relaxant effect of resveratrol on the rat rings of endothelium-denuded group was reduced compared with that of endothelium-intact group; the relaxant effect of resveratrol on rat rings was higher under the condition of Ca2+-free bath solution than that under the condition of Ca2+-contained bath solution. Resveratrol had a repressive effect on the aorta's contraction induced by intracellular calcium, but had no effect induced by extracellular calcium. Resveratrol relaxed the contractions induced by KCl 30 mmol x L(-1) as well as KCl 80 mmol x L(-1), but the contraction curve of KCl 80 mmol x L(-1) was shifted upward significantly. In the L-NNA group, the relaxant effect was attenuated by (26.0 +/- 4.6) %; but there was no change in the group of Glibenclamide ( P > 0.05).


CONCLUSIONS
The results indicate that resveratrol relaxes vascular smooth muscle in an endothelium dependent manner. The mechanisms for this phenomenon seem to be related with promoting synthesis and release of NO, opening Ca2+ activated K+ channel (KCa channel) as well as the inhibition of Ca2+ influx and release of Ca2+ from intracellular stores.
Zhang
Hong-yun
HY
Harbin Medical University, Harbin 150086, China.
Xu
Chang-qing
CQ
Li
Hong-zhu
HZ
Li
Bao-xin
BX
Zhang
Yan-qiao
YQ
Zhang
Yi-na
YN
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000502:physiology; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000037:antagonists & inhibitors; D011189:Potassium Chloride / Q000037:antagonists & inhibitors; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D000077185:Resveratrol; D013267:Stilbenes / Q000008:administration & dosage / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*
D004365:Drugs, Chinese Herbal; D013267:Stilbenes; D014665:Vasodilator Agents; D011189:Potassium Chloride; D000077185:Resveratrol; D005905:Glyburide; D002118:Calcium; D009638:Norepinephrine