Role of InsP3 and ryanodine receptors in the activation of capacitative Ca2+ entry by store depletion or hypoxia in canine pulmonary arterial smooth muscle cells
Role of InsP3 and ryanodine receptors in the activation of capacitative Ca2+ entry by store depletion or hypoxia in canine pulmonary arterial smooth muscle cells
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DOI：
10.1038/sj.bjp.0707357
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发表时间：
2007-09-01
影响因子：
7.3
通讯作者：
Hume, J. R.
中科院分区：
文献类型：
--
作者：
Ng, L. C.;Wilson, S. M.;Hume, J. R.
背景和目的：进行实验以确定犬肺动脉平滑肌细胞（PASMCs）中的容量性Ca 2+内流（CCE）是否依赖于InsP（3）受体或ryanodine受体，因为CCE的诱导依赖于这些细胞中功能分离的InsP（3）-和ryanodine-敏感的肌浆网（SR）Ca 2+储存的同时消耗。使用酶法从犬肺动脉中分离肌细胞，并在制备后8小时内使用。细胞溶质钙离子的测量进行了成像fura-2加载的个人心肌细胞灌注生理缓冲盐水溶液或无Ca 2 +.Key results：处理心肌细胞与10 μ M cyclopiazonic酸（CPA），去除细胞外钙离子，并简要地应用10 μ M咖啡因和10 μ M 5-羟色胺（5-HT）耗尽SR钙离子商店。细胞外Ca 2+再引入导致细胞溶质[Ca 2 +]升高至基线以上，表明CCE。InsP（3）受体抑制剂2-氨基联苯硼酸盐（50-75 μ M; 2-APB）和xestospongin-C（20 μ M; XeC）可消除CCE。然而，CCE不受10 μ M或300 μ M兰尼碱或10 μ M丹曲林的影响，这会改变兰尼碱受体的活性。然而，较高的丹曲林浓度（50 rho M）可抑制兰尼碱受体和InsP 3受体，并降低CCE。相反，缺氧激活的CCE不受XeC（20 μ M）的影响。结论和影响：结果提供证据表明，在犬PASMCs中，InsP 3和ryanodine SR Ca 2+商店耗尽激活的CCE依赖于功能性InsP（3）受体，而缺氧激活的CCE似乎不依赖于功能性InsP（3）受体。
Background and purpose: Experiments were performed to determine if capacitative Ca2+ entry (CCE) in canine pulmonary arterial smooth muscle cells ( PASMCs) is dependent on InsP(3) receptors or ryanodine receptors as induction of CCE is dependent on simultaneous depletion of the functionally separate InsP(3)- and ryanodine-sensitive sarcoplasmic reticulum (SR) Ca2+ stores in these cells.Experimental approach: Myocytes were isolated from canine pulmonary arteries using enzymatic procedures and were used within 8 h of preparation. Measurements of cytosolic Ca2+ were made by imaging fura-2 loaded individual myocytes that were perfused with physiological buffered saline solution with or without Ca2+.Key results: Treating myocytes with 10 mu M cyclopiazonic acid (CPA), removing extracellular Ca2+, and briefly applying 10 mu M caffeine and 10 mu M 5-hydroxytryptamine (5-HT) depleted SR Ca2+ stores. Extracellular Ca2+ reintroduction caused cytosolic [Ca2+] to elevate above baseline signifying CCE. The InsP(3) receptor inhibitors 2-aminobiphenylborate (50-75 mu M; 2-APB) and xestospongin-C (20 mu M; XeC) abolished CCE. Yet, CCE was unaffected by 10 mu M or 300 mu M ryanodine or 10 mu M dantrolene, which modify ryanodine receptor activity. Higher dantrolene concentrations (50 rho M), however, can inhibit both ryanodine receptors and InsP3 receptors, did reduce CCE. In contrast, CCE activated by hypoxia was unaffected by XeC (20 mu M).Conclusions and implications: The results provide evidence that CCE activated by depletion of both InsP3 and ryanodine SR Ca2+ stores in canine PASMCs is dependent on functional InsP(3) receptors, whereas the activation of CCE by hypoxia appears to be independent of functional InsP(3) receptors.