Flow does not alter eNOS phosphoryation at Ser1179 or Thr495 in preconstricted mouse mesenteric arteries.
Flow does not alter eNOS phosphoryation at Ser1179 or Thr495 in preconstricted mouse mesenteric arteries.
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DOI：
10.14814/phy2.13864
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发表时间：
2018-09
影响因子：
2.5
通讯作者：
Wolfert MR
中科院分区：
文献类型：
--
作者：
Looft-Wilson RC;Todd SE;Berberich KM;Wolfert MR
在动脉中，内皮依赖性血管舒张激动剂和流动诱导的剪切应力主要通过激活内皮酶eNOS引起血管舒张，eNOS产生一氧化氮，松弛血管平滑肌。激动剂激活eNOS部分通过增加Ser 1179的磷酸化和减少Thr 495的磷酸化。我们以前发现，预收缩的完整的，孤立的小鼠肠系膜动脉苯丙氨酸也引起Ser 1179和减少Thr 495 eNOS磷酸化，和顺序治疗与血管舒张激动剂乙酰胆碱没有引起任何进一步的变化，在这些网站的磷酸化，尽管产生血管舒张。目前的研究测试的假设，这些动脉中的管腔流动与苯肾上腺素预收缩也产生血管舒张，而在这些网站的磷酸化变化。从戊巴比妥（50 mg/kg，i. p.）麻醉的雄性C57/BL 6小鼠（7-20周龄）中分离的一级肠系膜动脉，插管、加压，并通过逐步增加管腔流量（15-120 μL/min）进行治疗。血流导致扩张，在~60 μL/min（31.3 ± 3.0%扩张）时达到稳定，并且在所有流速下均具有显著（P < 0.001）NOS依赖性（通过10−4 mol/L L-NAME处理确定）。在单独的动脉中，苯肾上腺素（10−5 mol/L）预收缩导致eNOS在Ser 1179处的磷酸化增加（P < 0.05），而在Thr 495处的磷酸化减少，但随后以60 μL/min的流量持续5或15 min并没有引起磷酸化的进一步变化，尽管会引起扩张。因此，血流诱导的扩张不需要改变这些eNOS磷酸化位点，而不是由苯肾上腺素刺激引起的，这表明eNOS在急性血流诱导的预收缩动脉扩张过程中被其他机制激活。
In arteries, endothelium‐dependent vasodilatory agonists and flow‐induced shear stress cause vasodilation largely by activation of the endothelial enzyme eNOS, which generates nitric oxide that relaxes vascular smooth muscle. Agonists activate eNOS in part through increased phosphorylation at Ser1179 and decreased phosphorylation at Thr495. We previously found that preconstriction of intact, isolated mouse mesenteric arteries with phenylephrine also caused increased Ser1179 and decreased Thr495 eNOS phosphorylation, and sequential treatment with the vasodilatory agonist acetylcholine did not cause any further change in phosphorylation at these sites, despite producing vasodilation. The present study tests the hypothesis that luminal flow in these arteries preconstricted with phenylephrine also produces vasodilation without phosphorylation changes at these sites. First‐order mesenteric arteries, isolated from male C57/BL6 mice (7–20 weeks of age) anesthetized with pentobarbital (50 mg/kg, i.p.), were cannulated, pressurized, and treated with stepped increases in luminal flow (15–120 μL/min). Flow resulted in dilation that plateaued at ~60 μL/min (31.3 ± 3.0% dilation) and was significantly (P < 0.001) NOS‐dependent at all flow rates (determined by 10−4 mol/L L‐NAME treatment). In separate arteries, preconstriction with phenylephrine (10−5 mol/L) resulted in increased eNOS phosphorylation at Ser1179 (P < 0.05) and decreased phosphorylation at Thr495, but subsequent flow at 60 μL/min for 5 or 15 min did not cause further changes in phosphorylation, despite causing dilation. Thus, flow‐induced dilation does not require changes in these eNOS phosphorylation sites beyond those induced by alpha1‐adrenergic stimulation with phenylephrine, indicating that eNOS is activated by other mechanisms during acute flow‐induced dilation of preconstricted arteries.