Sensitivity to endothelin-1 is decreased in isolated livers of endothelial constitutive nitric oxide synthase knockout mice.
Sensitivity to endothelin-1 is decreased in isolated livers of endothelial constitutive nitric oxide synthase knockout mice.
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DOI：
10.1186/1476-5926-5-9
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发表时间：
2006-12-05
期刊：
影响因子：
--
通讯作者：
Reichen, Jurg
中科院分区：
文献类型：
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作者：
De Gottardi, Andrea;Biecker, Erwin;Reichen, Jurg
背景：肝窦阻力受血管活性因子内皮素-1（ET-1）和一氧化氮（NO）的调节。在没有NO的情况下，预期对内皮素的血管收缩反应占主导地位。因此，我们假设内皮细胞NO合酶基因缺失的小鼠对内皮素的敏感性增加。在原位灌注的内皮型一氧化氮合酶（ecNOS）基因敲除和野生型小鼠的肝脏血管阻力内皮素的反应进行了评估。还收获肝脏用于RNA和蛋白质分离，分别用于定量PCR和Western印迹。内皮素受体，一氧化氮合酶，血红素氧合酶和肾上腺髓质素的同工酶的表达进行了quantitatives.Results：内皮素增加肝血管阻力的剂量依赖性的方式在这两个菌株，然而，这种增加是显着减少ecNOS基因敲除小鼠在生理浓度。血红素加氧酶和肾上腺髓质素的表达在两组中是相似的，而诱导型一氧化氮合酶（iNOS）蛋白在两种菌株中均未检测到。前原内皮素-1和ETB受体的mRNA水平在两种菌株中是可比的，而ETA受体的mRNA在ecNOS knockouts.CONCLUSION：ecNOS基因敲除小鼠的肝脏在生理浓度下对内皮素的敏感性降低，这是与ETA受体的表达减少，但不与其他因素，如iNOS，ETB受体，肾上腺髓质素或血红素加氧酶。进一步的研究表明，在ETA受体分布和/或受体下游的细胞内信号转导的适应性变化为目标。
BACKGROUND: Hepatic sinusoidal resistance is regulated by vasoactive factors including endothelin-1 (ET-1) and nitric oxide (NO). In the absence of NO, vasoconstrictor response to endothelin is expected to predominate. Therefore, we hypothesized sensitivity to endothelin to be increased in mice lacking the endothelial cell NO synthase gene. Response of vascular resistance to endothelin was assessed in the in situ perfused liver of endothelial constitutive nitric oxide synthase (ecNOS) knockout and wild type mice. Livers were also harvested for RNA and protein isolation for quantitative PCR and Western blotting, respectively. The expression of endothelin receptors, isoenzymes of NO synthase, heme-oxygenase and adrenomedullin was quantified.RESULTS: Endothelin increased hepatic vascular resistance in a dose-dependent manner in both strains; however, this increase was significantly less in ecNOS knockout mice at physiologic concentrations. Expression of heme-oxygenases and adrenomedullin was similar in both groups, whereas inducible nitric oxide synthase (iNOS) protein was not detectable in either strain. mRNA levels of pre-pro-endothelin-1 and ETB receptor were comparable in both strains, while mRNA for ETA receptor was decreased in ecNOS knockouts.CONCLUSION: Livers of ecNOS knockout mice have a decreased sensitivity to endothelin at physiologic concentrations; this is associated with a decreased expression of ETA receptors, but not with other factors, such as iNOS, ETB receptors, adrenomedullin or heme-oxygenase. Further studies targeting adaptive changes in ETA receptor distribution and/or intracellular signaling downstream of the receptor are indicated.