Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ontario, Canada.
Clin Sci (Lond). 2010 Mar 9;118(11):657-68. doi: 10.1042/CS20090352.
The present study investigated the role of ROS (reactive oxygen species) and COX (cyclo-oxygenase) in ethanol-induced contraction and elevation of [Ca2+]i (intracellular [Ca2+]). Vascular reactivity experiments, using standard muscle bath procedures, showed that ethanol (1-800 mmol/l) induced contraction in endothelium-intact (EC50: 306+/-34 mmol/l) and endothelium -denuded (EC50: 180+/-40 mmol/l) rat aortic rings. Endothelial removal enhanced ethanol-induced contraction. Preincubation of intact rings with L-NAME [NG-nitro-L-arginine methyl ester; non-selective NOS (NO synthase) inhibitor, 100 micromol/l], 7-nitroindazole [selective nNOS (neuronal NOS) inhibitor, 100 micromol/l], oxyhaemoglobin (NO scavenger, 10 micromol/l) and ODQ (selective inhibitor of guanylate cyclase enzyme, 1 micromol/l) increased ethanol-induced contraction. Tiron [O2- (superoxide anion) scavenger, 1 mmol/l] and catalase (H2O2 scavenger, 300 units/ml) reduced ethanol-induced contraction to a similar extent in both endothelium-intact and denuded rings. Similarly, indomethacin (non-selective COX inhibitor, 10 micromol/l), SC560 (selective COX-1 inhibitor, 1 micromol/l), AH6809 [PGF2alpha (prostaglandin F2alpha)] receptor antagonist, 10 micromol/l] or SQ29584 [PGH2(prostaglandin H2)/TXA2 (thromboxane A2) receptor antagonist, 3 micromol/l] inhibited ethanol-induced contraction in aortic rings with and without intact endothelium. In cultured aortic VSMCs (vascular smooth muscle cells), ethanol stimulated generation of O2- and H2O2. Ethanol induced a transient increase in [Ca2+]i, which was significantly inhibited in VSMCs pre-exposed to tiron or indomethacin. Our data suggest that ethanol induces vasoconstriction via redox-sensitive and COX-dependent pathways, probably through direct effects on ROS production and Ca2+ signalling. These findings identify putative molecular mechanisms whereby ethanol, at high concentrations, influences vascular reactivity. Whether similar phenomena occur in vivo at lower concentrations of ethanol remains unclear.
本研究探讨了 ROS（活性氧）和 COX（环氧化酶）在乙醇诱导的收缩和 [Ca2+]i（细胞内 [Ca2+]）升高中的作用。使用标准肌肉浴程序进行血管反应性实验，结果表明乙醇（1-800mmol/l）诱导内皮完整（EC50：306+/-34mmol/l）和内皮去除（EC50：180+/-40mmol/l）大鼠主动脉环收缩。内皮去除增强了乙醇诱导的收缩。完整环用 L-NAME [NG-硝基-L-精氨酸甲酯；非选择性 NOS（一氧化氮合酶）抑制剂，100μmol/l]、7-硝基吲唑[选择性 nNOS（神经元 NOS）抑制剂，100μmol/l]、氧合血红蛋白（NO 清除剂，10μmol/l) 和 ODQ（选择性鸟苷酸环化酶酶抑制剂，1μmol/l) 预孵育增加了乙醇诱导的收缩。Tiron [O2-（超氧阴离子）清除剂，1mmol/l] 和过氧化氢酶（H2O2 清除剂，300 单位/ml）以相似的程度减少了内皮完整和去除的环中的乙醇诱导的收缩。同样，吲哚美辛（非选择性 COX 抑制剂，10μmol/l）、SC560（选择性 COX-1 抑制剂，1μmol/l）、AH6809 [PGF2alpha（前列腺素 F2alpha)] 受体拮抗剂，10μmol/l] 或 SQ29584 [PGH2（前列腺素 H2）/TXA2（血栓烷 A2）受体拮抗剂，3μmol/l] 抑制了内皮完整和不完整的主动脉环中的乙醇诱导的收缩。在培养的主动脉 VSMCs（血管平滑肌细胞）中，乙醇刺激 O2-和 H2O2 的产生。乙醇诱导 [Ca2+]i 的短暂增加，在用 Tiron 或吲哚美辛预先暴露的 VSMCs 中，这种增加明显受到抑制。我们的数据表明，乙醇通过氧化还原敏感和 COX 依赖的途径诱导血管收缩，可能通过直接影响 ROS 产生和 Ca2+信号转导。这些发现确定了乙醇在高浓度下影响血管反应性的潜在分子机制。在较低浓度的乙醇下，是否存在类似的现象尚不清楚。
