Coskun Bahar, Soylemez Selen, Parlar Ali Ihsan, Tulga Ulus A, Fehmi Katircioglu S, Akar Fatma
Faculty of Pharmacy, Department of Pharmacology, Gazi University, Etiler, Turkey.
J Cardiovasc Pharmacol. 2006 Mar;47(3):437-45. doi: 10.1097/01.fjc.0000211798.91023.14.
The present study aims to examine whether resveratrol, a natural antioxidant present in red wine, restores the tolerance to nitroglycerin (GTN) on isolated human internal mammary artery (IMA), using an in vitro model of nitrate tolerance. IMA rings were obtained from 53 male patients undergoing coronary bypass operation. Nitrate tolerance was induced by incubating the artery ring with 100 microM GTN for 90 minutes. Concentration-response curves to GTN (10(-9) to 10(-4) M) were obtained on IMA rings precontracted with noradrenaline. A low concentration (5 microM) of lucigenin was used as a tool to measure superoxide production in IMA segments. GTN produced concentration-dependent relaxation in isolated human IMA rings. Preexposure of artery rings to GTN reduced the relaxations to GTN [E(max) values: 105 +/- 2% and 76 +/- 3%, n = 10 to 12, P < 0.05; EC(50) values (-log M): 6.72 +/- 0.05 and 4.95 +/- 0.06, P < 0.05, respectively]. Relaxation to sodium nitroprusside remained unchanged. Diminished relaxation to GTN is partially restored after removing endothelium or L(G)-nitro-L-arginine (L-NOARG, 10 M) or superoxide dismutase (20 and 200 U/mL) or catalase (200 U/mL) pretreatments. Pretreatments with resveratrol (1, 10, and 20 microM) for 20 minutes relatively improved the reduced relaxation to GTN in tolerant IMA rings. Coadministration of L-NOARG with resveratrol did not abolish the beneficial effect of resveratrol on nitrate tolerance. The inhibitory effect of resveratrol on GTN-induced tolerance was not abolished in arterial rings without endothelium. Exposure to GTN increased superoxide production in IMA segments with endothelium. Endothelium denudation, L-NOARG, or superoxide dismutase pretreatments markedly inhibited the increased superoxide production in tolerant arteries. Resveratrol (1 and 10 microM) almost completely abolished basal or NAD(P)H-stimulated superoxide production in tolerant and nontolerant arteries. Vascular tolerance to GTN, in in vitro tolerant human IMA rings, can be induced by endothelial superoxide anions. Resveratrol partially restored the reduced relaxation to GTN by inhibiting NAD(P)-derived superoxide production in endothelium.
本研究旨在利用硝酸盐耐受性的体外模型，检验红酒中存在的天然抗氧化剂白藜芦醇是否能恢复离体人乳内动脉（IMA）对硝酸甘油（GTN）的耐受性。从53例接受冠状动脉搭桥手术的男性患者获取IMA环。通过将动脉环与100微摩尔GTN孵育90分钟诱导产生硝酸盐耐受性。在预先用去甲肾上腺素预收缩的IMA环上获得对GTN（10⁻⁹至10⁻⁴摩尔）的浓度 - 反应曲线。使用低浓度（5微摩尔）的光泽精作为测量IMA节段中超氧化物产生的工具。GTN在离体人IMA环中产生浓度依赖性舒张。动脉环预先暴露于GTN会降低对GTN的舒张反应[E(max)值：105±2%和76±3%，n = 10至12，P < 0.05；EC(50)值（-log M）：6.72±0.05和4.95±0.06，P < 0.05]。对硝普钠的舒张反应保持不变。去除内皮或用L(G)-硝基-L-精氨酸（L-NOARG，10摩尔）或超氧化物歧化酶（20和200单位/毫升）或过氧化氢酶（200单位/毫升）预处理后，对GTN降低的舒张反应部分恢复。用白藜芦醇（1、10和20微摩尔）预处理20分钟相对改善了耐受性IMA环中对GTN降低的舒张反应。L-NOARG与白藜芦醇共同给药并未消除白藜芦醇对硝酸盐耐受性的有益作用。在无内皮的动脉环中，白藜芦醇对GTN诱导的耐受性的抑制作用未被消除。暴露于GTN会增加有内皮的IMA节段中的超氧化物产生。内皮剥脱、L-NOARG或超氧化物歧化酶预处理显著抑制了耐受性动脉中超氧化物产生的增加。白藜芦醇（1和10微摩尔）几乎完全消除了耐受性和非耐受性动脉中基础或NAD(P)H刺激的超氧化物产生。在体外耐受性人IMA环中，血管对GTN的耐受性可由内皮超氧阴离子诱导。白藜芦醇通过抑制内皮中NAD(P)衍生的超氧化物产生部分恢复了对GTN降低的舒张反应。
