ROLE OF CALCIUM AND CALMODULIN IN FLOW-INDUCED NITRIC-OXIDE PRODUCTION IN ENDOTHELIAL-CELLS
ROLE OF CALCIUM AND CALMODULIN IN FLOW-INDUCED NITRIC-OXIDE PRODUCTION IN ENDOTHELIAL-CELLS
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DOI：
10.1152/ajpcell.1994.266.3.c628
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发表时间：
1994-03-01
影响因子：
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通讯作者：
FRANGOS, JA
中科院分区：
文献类型：
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作者：
KUCHAN, MJ;FRANGOS, JA
这些实验表明，培养的内皮细胞（EC）暴露于明确的层流导致NO产生率升高。通过NOx（NO2- + NO32-）的释放和细胞内鸟苷3 '，5'-环一磷酸（cGMP）浓度监测NO的产生。NO合酶（NOS）抑制剂阻断了NOx和cGMP的流动介导的刺激，表明这两种测量反映NO的产生。暴露于层流增加NO的释放在一个两相的方式，与最初的快速生产随之而来的开始流动，然后由一个不太迅速，持续的生产。NO产量的类似快速增加是由于流量增加超过预先存在的水平。在生理范围内（6-25 dyn/cm（2）），NO的快速初始产生不依赖于切应力，但可能依赖于切应力的变化率。NO的持续释放依赖于生理水平的切应力。钙（Ca 2+）或钙调素（CaM）的依赖性的初始和持续生产的NO与缓激肽（BK）介导的NO生产进行了比较。BK和初始生产都被Ca 2+和CaM拮抗剂抑制。与此相反，持续的剪切应力介导的NO的生产没有受到影响，尽管持续的功能存在的拮抗剂。地塞米松对初始或持续剪切应力介导的NO产生没有影响。因此，诱导型NOS并不能解释持续剪切应力介导的NO产生的明显Ca 2 +/CaM独立性。总之，这些数据表明，初始层流流体流刺激的NO生产是非常相似的BK介导的生产：快速和Ca 2 +/CaM依赖。持续暴露刺激NO生产通过剪切应力在生理上Ca 2 +/CaM-独立（激活静息水平）的方式。
These experiments demonstrate that exposure of cultured endothelial cells (EC) to well-defined laminar fluid flow results in an elevated rate of NO production. NO production was monitored by release of NOx (NO2- + NO32-) and by cellular guanosine 3',5'-cyclic monophosphate (cGMP) concentration. NO synthase (NOS) inhibitor blocked the flow-mediated stimulation of both NOx and cGMP, indicating that both measurements reflect NO production. Exposure to laminar flow increased NO release in a biphasic manner, with an initial rapid production consequent to the onset of flow followed by a less rapid, sustained production. A similar rapid increase in NO production resulted from an increase in flow above a preexisting level. The rapid initial production of NO was not dependent on shear stress within a physiological range (6-25 dyn/cm(2)) but may be dependent on the rate of change in shear stress. The sustained release of NO was dependent on physiological levels of shear stress. The calcium (Ca2+) or calmodulin (CaM) dependence of the initial and sustained production of NO was compared with bradykinin (BK)-mediated NO production. Both BK and the initial production were inhibited by Ca2+ and CaM antagonists. In contrast, the sustained shear stress-mediated NO production was not affected, despite the continued functional presence of the antagonists. Dexamethasone had no effect on either the initial or the sustained shear stress-mediated NO production. An inducible NOS does not, therefore, explain the apparent Ca2+/CaM independence of the sustained shear stress-mediated NO production. In summary, these data reveal that initial laminar fluid flow-stimulated NO production is very similar to BK-mediated production: rapid and Ca2+/CaM dependent. Continued exposure stimulates NO production via shear stress in a physiologically Ca2+/CaM-independent (activated by resting levels) manner.