Matrougui K, Eskildsen-Helmond Y E, Fiebeler A, Henrion D, Levy B I, Tedgui A, Mulvany M J
Department of Pharmacology, University of Aarhus, Aarhus, Denmark.
Hypertension. 2000 Oct;36(4):617-21. doi: 10.1161/01.hyp.36.4.617.
The activation of extracellular signal-regulated kinases 1/2 (ERK1/2) was assessed in isolated rat mesenteric resistance arteries (200-micrometer diameter) in a pressure myograph and stimulated for 5 minutes by angiotensin II (Ang II, 0.1 micromol/L) with a pressure of 70 mm Hg. ERK1/2 activity was measured by using an in-gel assay, and ERK1/2 phosphorylation was measured by Western blot analysis with use of a phospho-specific ERK1/2 antibody. Ang II (0.1 micromol/L) induced contraction (28% of phenylephrine contraction, 10 micromol/L). ERK kinase inhibitor PD98059 (10 micromol/L) attenuated this contraction by 36% but not that to phenylephrine or K(+) (60 mmol/L). In unpressurized arteries, Ang II increased ERK1/2 activity by 26%, and pressure (70 mm Hg) itself increased ERK1/2 activity by 72%. Ang II and pressure together acted synergistically, increasing ERK1/2 activity by 264%. Thus, in pressurized vessels, Ang II (0.1 micromol/L) increased ERK1/2 activity by 112%, calculated as [(364/172)-1]x100, which was confirmed by a measured 72% increase in ERK1/2 phosphorylation. Ang II type 1 receptor blockade by candesartan (10 micromol/L) abolished the Ang II-induced increase in ERK1/2 activity, but Ang II type 2 receptor blockade (PD123319, 10 micromol/L) did not. The Ang II-induced increase in ERK1/2 activity was inhibited by protein kinase C inhibitors Ro-31-8220 (1 micromol/L) and Go-6976 (300 nmol/L) and tyrosine kinase inhibitors genistein (1 micromol/L, general) and herbimycin A (1 micromol/L, c-Src family). The present findings show for the first time in intact resistance arteries that ERK1/2 activation is rapidly regulated by Ang II, is synergistic with pressure, and is involved in contraction. The ERK1/2 signaling pathway apparently includes upstream protein kinase C and c-Src.
在压力肌动描记仪中，对分离的大鼠肠系膜阻力动脉（直径200微米）进行细胞外信号调节激酶1/2（ERK1/2）激活评估，用血管紧张素II（Ang II，0.1微摩尔/升）在70毫米汞柱压力下刺激5分钟。使用凝胶内分析法测量ERK1/2活性，使用磷酸化特异性ERK1/2抗体通过蛋白质印迹分析测量ERK1/2磷酸化。Ang II（0.1微摩尔/升）诱导收缩（为去氧肾上腺素收缩的28%，10微摩尔/升）。ERK激酶抑制剂PD98059（10微摩尔/升）使该收缩减弱36%，但对去氧肾上腺素或钾（60毫摩尔/升）诱导的收缩无影响。在未加压动脉中，Ang II使ERK1/2活性增加26%，压力（70毫米汞柱）本身使ERK1/2活性增加72%。Ang II和压力共同起协同作用，使ERK1/2活性增加264%。因此，在加压血管中，Ang II（0.1微摩尔/升）使ERK1/2活性增加112%，计算方法为[（364/172）-1]×100，这通过测量ERK1/2磷酸化增加72%得到证实。坎地沙坦（10微摩尔/升）阻断1型Ang II受体可消除Ang II诱导的ERK1/2活性增加，但2型Ang II受体阻断剂（PD123319，10微摩尔/升）则无此作用。蛋白激酶C抑制剂Ro-31-8220（1微摩尔/升）和Go-6976（300纳摩尔/升）以及酪氨酸激酶抑制剂染料木黄酮（1微摩尔/升，通用）和赫司特霉素A（1微摩尔/升，c-Src家族）可抑制Ang II诱导的ERK1/2活性增加。本研究结果首次在完整的阻力动脉中表明，ERK1/2激活受Ang II快速调节，与压力协同作用，并参与收缩。ERK1/2信号通路显然包括上游蛋白激酶C和c-Src。
