CYTOCHROME-P450 MONO-OXYGENASE-REGULATED SIGNALING OF CA2+ ENTRY IN HUMAN AND BOVINE ENDOTHELIAL-CELLS
CYTOCHROME-P450 MONO-OXYGENASE-REGULATED SIGNALING OF CA2+ ENTRY IN HUMAN AND BOVINE ENDOTHELIAL-CELLS
复制标题
DOI：
10.1113/jphysiol.1995.sp020515
复制
发表时间：
1995-01-15
影响因子：
5.5
通讯作者：
STUREK, M
中科院分区：
文献类型：
--
作者：
GRAIER, WF;SIMECEK, S;STUREK, M
1. 我们验证了一种假设，即激动剂刺激Ca2+进入，从而在血管内皮细胞中形成内皮源性一氧化氮（EDNO），与微粒体P450单加氧酶（P450 MO）的激活和5,6-环氧二碳三烯酸（5,6- eet）的生物合成有关。几种P450抑制剂减少了持续的[Ca2+](i)对激动剂或激动剂或atp酶抑制剂刺激的细胞内Mn2+内流的平台反应被P450抑制剂阻止。组胺或atp酶抑制剂刺激的EDNO形成被P450抑制剂强烈减弱（50-83%），而对Ca2+离子载体A23187的EDNO形成没有任何影响，这表明EDNO合成的减少是由于这些化合物抑制Ca2+进入。-萘黄酮增强激动剂诱导P450 MO分别诱导60%和53%的Ca2+和Mn2+内流。细胞内Ca2+释放保持不变。P450 MO产物5,6- eet （< 156 nmol 1(-1)）激活Ca2+/Mn2+进入，而不消耗细胞内Ca2+储存。5,8- eet刺激的Ca2+/Mn2+进入不受P450抑制剂的影响。与缓激素刺激的Ca2+进入途径一样，5，b - eet激活的Ca2+进入途径对Mn2+和Ba2+具有渗透性，对Ni2+， La3+和膜去极化敏感，对细胞外Na+或有机Ca2+拮抗剂的去除不敏感。, nitrendipine.7。在5,6- eet存在的情况下，缓激肽的刺激只是短暂地增加[Ca2+](i)。反之亦然，在缓激素刺激的细胞中，5,6- eet不能进一步增加[Ca2+](i)。缓激肽和5,6- eet共同刺激引起的持续的[Ca2+](i)平台期与单独使用缓激肽或5,6- eet时观察到的相同。这些结果表明，P450 MO产物5,6- eet诱导的Ca2+进入与缓激肽刺激观察到的Ca2+进入没有区别。所有数据都支持我们的假设，即内皮Ca2+储存的消耗激活微粒体P450 MO，从而合成5,6- eet。我们认为花生四烯酸代谢物5,6- eet或其代谢物之一是激活内皮细胞Ca2+进入的第二信使。
1. We tested the hypothesis that agonist-stimulated Ca2+ entry, and thus formation of endothelium-derived nitric oxide (EDNO) in vascular endothelial cells, is related to activation of microsomal P450 mono-oxygenase (P450 MO) and the biosynthesis of 5,6-epoxyeicosatrienoic acid (5,6-EET).2. Several P450 inhibitors diminished the sustained [Ca2+](i) plateau response to agonist or intracellular Mn2+ influx stimulated by agonists or ATPase inhibitors was prevented by P450 inhibitors.3. Histamine- or ATPase inhibitor-stimulated formation of EDNO was strongly attenuated (50-83%) by P450 inhibitors, without any effect on EDNO formation by the Ca2+ ionophore A23187, indicating that decreased EDNO synthesis is due specifically to the inhibition of Ca2+ entry by these compounds.4. Induction of P450 MO by beta-naphthoflavone potentiated agonist-induced Ca2+ and Mn2+ influx by 60 and 53%, respectively. Intracellular Ca2+ release remained unchanged.5. The P450 MO product, 5,6-EET (< 156 nmol 1(-1)), activated Ca2+/Mn2+ entry without any depletion of intracellular Ca2+ stores. The 5,8-EET-stimulated Ca2+/Mn2+ entry was not affected by P450 inhibitors.6. As with the bradykinin-stimulated Ca2+ entry pathway, the 5,B-EET-activated Ca2+ entry pathway was permeable to Mn2+ and Ba2+, sensitive to Ni2+, La3+ and membrane depolarization, and insensitive to the removal of extracellular Na+ or the organic Ca2+ antagonist., nitrendipine.7. In the presence of 5,6-EET, stimulation with bradykinin only transiently increased [Ca2+](i). Vice versa, 5,6-EET failed to increase [Ca2+](i) further in bradykinin-stimulated cells. The sustained [Ca2+](i) plateau phase induced by a co-stimulation with bradykinin and 5,6-EET was identical to that observed with bradykinin or 5,6-EET alone.8. These results demonstrate that Ca2+ entry induced by the P450 MO product, 5,6-EET, is indistinguishable to that observed by stimulation with bradykinin.9. All data support our hypothesis that depletion of endothelial Ca2+ stores activates microsomal P450 MO which in turn synthesizes 5,6-EET. We propose that the arachidonic acid metabolite 5,6-EET or one of its metabolites is a second messenger for activation of endothelial Ca2+ entry.