Research Unit, Division of Internal Medicine, University Hospital of Zurich, Switzerland.
Eur J Pharmacol. 2011 May 1;658(1):22-7. doi: 10.1016/j.ejphar.2010.09.053. Epub 2010 Sep 22.
Activation of mitogen-activated protein kinases (MAPKs) is important for vascular contraction. Decreased nitric oxide availability combined with activation of MAPKs contributes to an increase in vascular tone. In this study, we have determined the involvement of extracellular signal-regulated kinases1/2 (ERK1/2) and c-Jun N-terminal kinases (JNKs) in reactivity of mouse aortae in the absence of nitric oxide. Additionally, we have examined the contribution of these kinases to endothelium-dependent and prostaglandin F(2α) (PGF(2α))-induced contractions. Precontracted aortic rings were treated with MAPK/ERK kinase1/2 (MEK1/2) inhibitor U0126 or JNKs inhibitor SP600125 to determine reactivity after inhibition of nitric oxide synthase using organ bath chambers. Additionally, rings were pretreated with or without these inhibitors to assess PGF(2α)- and acetylcholine-induced, endothelium-dependent contractions. Specificity of the inhibitors was evaluated in each aortic ring by determining the phosphorylation levels of ERK1/2 and c-Jun using Bio-Plex™ phospho-protein detection kit. In the absence of nitric oxide both inhibitors caused relaxation, and the dilator response was increased by 2.5-fold using SP600125 in comparison with U0126. Transient endothelium-dependent contractions were blocked by U0126, whereas SP600125 strongly attenuated sustained PGF(2α)-induced contractions. U0126 inhibited only phosphorylation of ERK1/2, while SP600125 at higher concentrations not only inhibited phosphorylation of c-Jun but also ERK1/2 phosphorylation. In conclusion, the present study demonstrates that in aortae inhibition of activated ERK1/2 and JNKs mediates vascular relaxation, even in the absence of nitric oxide. Activation of ERK1/2 contributes predominantly to transient endothelium-dependent contractions while JNKs, possibly synergistically with ERK1/2, leads to sustained PGF(2α)-induced contractions.
丝裂原活化蛋白激酶（MAPKs）的激活对于血管收缩很重要。一氧化氮供应减少加上 MAPKs 的激活导致血管张力增加。在这项研究中，我们已经确定了细胞外信号调节激酶 1/2（ERK1/2）和 c-Jun N 末端激酶（JNKs）在缺乏一氧化氮的情况下对小鼠主动脉反应性的参与。此外，我们还研究了这些激酶对内皮依赖性和前列腺素 F（2α）（PGF（2α））诱导收缩的贡献。用 MAPK/ERK 激酶 1/2（MEK1/2）抑制剂 U0126 或 JNKs 抑制剂 SP600125 处理预收缩的主动脉环，以确定用器官浴室抑制一氧化氮合酶后反应性。此外，通过用或不用这些抑制剂预处理环来评估 PGF（2α）-和乙酰胆碱诱导的内皮依赖性收缩。通过使用 Bio-Plex™磷酸蛋白检测试剂盒确定 ERK1/2 和 c-Jun 的磷酸化水平，在每个主动脉环中评估抑制剂的特异性。在缺乏一氧化氮的情况下，两种抑制剂均引起松弛，与 U0126 相比，SP600125 使扩张反应增加了 2.5 倍。U0126 阻断短暂的内皮依赖性收缩，而 SP600125 强烈减弱持续的 PGF（2α）诱导的收缩。U0126 仅抑制 ERK1/2 的磷酸化，而 SP600125 在较高浓度下不仅抑制 c-Jun 的磷酸化，而且还抑制 ERK1/2 的磷酸化。总之，本研究表明，在主动脉中，抑制激活的 ERK1/2 和 JNKs 介导血管松弛，即使在缺乏一氧化氮的情况下也是如此。ERK1/2 的激活主要有助于短暂的内皮依赖性收缩，而 JNKs 可能与 ERK1/2 协同作用，导致持续的 PGF（2α）诱导的收缩。
