Department of Psychiatric Nursing and Human Sciences, Laboratory of Pharmacology, College of Nursing of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
Vascul Pharmacol. 2012 Jan-Feb;56(1-2):74-83. doi: 10.1016/j.vph.2011.11.006. Epub 2011 Dec 3.
We investigated the role of reactive oxygen species (ROS) and nitric oxide (NO) in ethanol-induced relaxation. Vascular reactivity experiments showed that ethanol (0.03-200 mmol/L) induced relaxation in endothelium-intact and denuded rat aortic rings isolated from male Wistar rats. Pre-incubation of intact or denuded rings with l-NAME (non selective NOS inhibitor, 100 μmol/L), 7-nitroindazole (selective nNOS inhibitor, 100 μmol/L), ODQ (selective inhibitor of guanylyl cyclase enzyme, 1 μmol/L), glibenclamide (selective blocker of ATP-sensitive K(+) channels, 3 μmol/L) and 4-aminopyridine (selective blocker of voltage-dependent K(+) channels, 4-AP, 1 mmol/L) reduced ethanol-induced relaxation. Similarly, tiron (superoxide anion (O(2)(-)) scavenger, 1 mmol/L) and catalase (hydrogen peroxide (H(2)O(2)) scavenger, 300 U/mL) reduced ethanol-induced relaxation to a similar extent in both endothelium-intact and denuded rings. Finally, prodifen (non-selective cytochrome P450 enzymes inhibitor, 10 μmol/L) and 4-methylpyrazole (selective alcohol dehydrogenase inhibitor, 10 μmol/L) reduced ethanol-induced relaxation. In cultured aortic vascular smooth muscle cells (VSMCs), ethanol stimulated generation of NO, which was significantly inhibited by l-NAME. In endothelial cells, flow cytometry studies showed that ethanol increased cytosolic Ca(2+) concentration ([Ca(2+)]c), O(2)(-) and cytosolic NO concentration ([NO]c). Tiron inhibited ethanol-induced increase in [Ca(2+)]c and [NO]c. The major new finding of this work is that ethanol induces relaxation via redox-sensitive and NO-cGMP-dependent pathways through direct effects on ROS production and NO signaling. These findings identify putative molecular mechanisms whereby ethanol, at pharmacological concentrations, influences vascular reactivity.
我们研究了活性氧（ROS）和一氧化氮（NO）在乙醇诱导的松弛中的作用。血管反应性实验表明，乙醇（0.03-200mmol/L）可诱导雄性 Wistar 大鼠分离的内皮完整和去内皮大鼠主动脉环松弛。用 l-NAME（非选择性 NOS 抑制剂，100μmol/L）、7-硝基吲唑（选择性 nNOS 抑制剂，100μmol/L）、ODQ（选择性鸟苷酸环化酶酶抑制剂，1μmol/L）、格列本脲（ATP 敏感性 K+通道选择性阻断剂，3μmol/L）和 4-氨基吡啶（电压依赖性 K+通道选择性阻断剂，4-AP，1mmol/L）预处理完整或去内皮环可降低乙醇诱导的松弛。同样，tiron（超氧阴离子（O2-）清除剂，1mmol/L）和过氧化氢酶（H2O2 清除剂，300U/mL）可降低内皮完整和去内皮环中乙醇诱导的松弛。最后，丙氧芬（非选择性细胞色素 P450 酶抑制剂，10μmol/L）和 4-甲基吡唑（选择性醇脱氢酶抑制剂，10μmol/L）降低了乙醇诱导的松弛。在培养的主动脉血管平滑肌细胞（VSMCs）中，乙醇刺激 NO 的产生，l-NAME 可显著抑制 NO 的产生。在内皮细胞中，流式细胞术研究表明，乙醇增加了细胞浆 Ca2+浓度([Ca2+]c)、O2-和细胞浆 NO 浓度([NO]c)。tiron 抑制乙醇诱导的[Ca2+]c 和 [NO]c 增加。这项工作的主要新发现是，乙醇通过直接影响 ROS 产生和 NO 信号转导，通过氧化还原敏感和 NO-cGMP 依赖途径诱导松弛。这些发现确定了乙醇在药理学浓度下影响血管反应性的潜在分子机制。
