Serotonin stimulates protein tyrosyl phosphorylation and vascular contraction via tyrosine kinase.
Serotonin stimulates protein tyrosyl phosphorylation and vascular contraction via tyrosine kinase.
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血清素通过酪氨酸激酶刺激蛋白质酪氨酰磷酸化和血管收缩。
DOI：
10.1159/000159156
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发表时间：
1996
影响因子：
1.7
通讯作者：
Webb,RC
中科院分区：
文献类型：
--
作者：
Watts,SW;Yeum,CH;Campbell,G;Webb,RC
5-羟色胺（5-HT， 5-羟色胺）是血管平滑肌中的一种丝裂原，高血压和动脉粥样硬化患者血管对5-HT的反应性显著增强。我们已经验证了酪氨酸激酶（对有丝分裂很重要的酶）可能在5- ht诱导的血管平滑肌收缩中起作用的假设。将剥去内皮的大鼠颈动脉和主动脉螺旋条置于组织浴中测量收缩力。酪氨酸激酶抑制剂染料木黄酮（5 × 10-6M）使剥去内皮的颈动脉条带的5- ht效价降低约4倍，并使最大收缩量减少至5- ht（58%对照）。染料木黄酮的无活性同系物大豆苷元（5 × 10-6M）没有降低颈动脉对5- ht的最大收缩，但使5- ht浓度反应曲线向右移动3倍。另一种酪氨酸激酶抑制剂Tyrphostin 23 （5 × 10-5M）使颈动脉5- ht的效价降低4倍，并使颈动脉5- ht的最大收缩量降低（10%对照）。两种酪氨酸激酶抑制剂均未减少或改变phorbor -12,13-二丁酸盐（10-9至10-5M）引起的收缩，表明phorbor -酯敏感的蛋白激酶C亚型不受影响。kcl诱导的收缩被tyrphostin 23（38.6%对照）显著抑制，而染料木素和大豆黄酮则不受抑制，表明tyrphostin 23而不是染料木素可能抑制电压门控钙通道以降低收缩性。使用抗磷酸酪氨酸抗体的Western blot分析证实，5-HT在培养的主动脉平滑肌细胞中产生了42-kD蛋白的磷酸酪氨酸免疫反应性的时间和浓度依赖性增加。用抗丝裂原活化蛋白（MAP）激酶抗体进行免疫沉淀，表明42-kD蛋白很可能是MAP激酶。5-羟色胺（10-5M）刺激全主动脉收缩，增加抗磷酸酪氨酸免疫反应性。重要的是，染料木素而不是大豆苷元使主动脉收缩向5-HT转移（向右5倍）并减少（69%对照）。这些发现表明：(1)酪氨酸激酶激活可能部分介导动脉平滑肌对5-HT的收缩；(2)tyrphostin 23在一定程度上是非选择性的；(3)5-HT刺激酪氨酸激酶，这可以通过培养的主动脉平滑肌细胞和主动脉组织中酪氨酸磷酸化蛋白的增加来证明。这些发现不仅对理解5-HT信号转导的新途径有重要意义，而且对生长和/或对5-HT的收缩性增加的血管疾病（如高血压、动脉粥样硬化）也有重要意义。
Serotonin (5-HT, 5-hydroxytryptamine) is a mitogen in vascular smooth muscle and vascular reactivity to 5-HT is significantly enhanced in hypertension and atherosclerosis. We have tested the hypothesis that tyrosine kinases, enzymes important for mitogenesis, may play a role in 5-HT-induced vascular smooth muscle contractility. Helical strips of rat carotid artery and aorta denuded of endothelium were mounted in tissue baths for measurement of contractile force. The tyrosine kinase inhibitor genistein (5 × 10-6M) decreased the potency of 5-HT approximately 4-fold and reduced maximal contraction to 5-HT in carotid arterial strips denuded of endothelium (58% control). Genistein’s inactive congener daidzein (5 × 10-6M)did not reduce maximal contraction to 5-HT in carotid arteries but did shift the 5-HT concentration response curve 3-fold to the right. Tyrphostin 23 (5 × 10–5M), another tyrosine kinase inhibitor, decreased the potency of 5-HT 4-fold and reduced the maximal contraction to 5-HT in the carotid artery (10% control). Contractions induced by phorbol-12,13-dibutyrate (10-9to 10-5M)were not reduced or shifted by either tyrosine kinase inhibitor, indicating that phorbol-ester-sensitive protein kinase C isoforms were not affected. KCl-induced contraction was shifted 2-fold and the maximum significantly inhibited by tyrphostin 23 (38.6% control) but not genistein or daidzein, indicating that tyrphostin 23 but not genistein may inhibit voltage-gated calcium channels to reduce contractility. Western blot analysis using antiphosphotyrosine antibody confirmed that 5-HT produced a time- and concentration-dependent increase in the phosphotyrosine immunoreactivity of a 42-kD protein in cultured aortic smooth muscle cells. Lysate immunoprecipitation with an anti-mitogen-activated-protein (MAP)-kinase antibody indicated that the 42-kD protein was most likely a MAP kinase. 5-HT (10-5M)stimulated contraction and increased antiphosphotyrosine immunoreactivity in whole aorta mounted in tissue baths. Importantly, aortic contraction to 5-HT was shifted (5-fold rightward) and reduced (69% control) by genistein but not daidzein. These findings demonstrate that (1) tyrosine kinase activation may partially mediate contractility to 5-HT in arterial smooth muscle, (2) tyrphostin 23 is somewhat nonselective and (3) 5-HT stimulates tyrosine kinase as documented by increased tyrosyl phosphorylation of proteins in cultured aortic smooth muscle cells and aortic tissue in active contraction of 5-HT. These findings have significant implications not only in understanding a novel pathway of 5-HT signal transduction but also in vascular diseases in which growth and/or contractility to 5-HT is increased (e.g. hypertension, atherosclerosis).