Acute hypoxia activates store-operated Ca2+ entry and increases intracellular Ca2+ concentration in rat distal pulmonary venous smooth muscle cells
Acute hypoxia activates store-operated Ca2+ entry and increases intracellular Ca2+ concentration in rat distal pulmonary venous smooth muscle cells
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DOI：
10.3978/j.issn.2072-1439.2013.08.68
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发表时间：
2013-10-01
影响因子：
2.5
通讯作者：
Wang, Jian
中科院分区：
文献类型：
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作者：
Peng, Gongyong;Ran, Pixin;Wang, Jian
原理：暴露在急性缺氧环境中会导致肺动脉(PA)和肺静脉(PV)的血管收缩。动脉侧的机制已经得到了广泛的研究。目的：探讨急性缺氧是否引起细胞内钙离子浓度([Ca~(2+)](I))升高，方法：用荧光显微镜和Fura-2测定4%O-2对分离的大鼠肺静脉平滑肌细胞[Ca~(2+)](I)和钙离子内流(SOCE)的影响。实验结果和主要结果：在含环鸟苷酸的无钙Krebs Ringer碳酸氢钠溶液(KRBS)灌流的PVSMC中，耗尽肌浆网(SR)中的Ca~(2+)贮备量；硝苯地平阻止钙通过L型电压依赖性钙通道(VDCC)内流。低氧显著增强细胞外[Ca~(2+)]恢复引起的[Ca~(2+)](I)升高和细胞外Mn2+对Fura-2荧光的猝灭速率。此外，SOCC拮抗剂SKF-96365和NiCl2可完全阻断正常盐液灌流的PVSMC内[Ca~(2+)](I)的升高，但对60 mM KCl的[Ca~(2+)](I)反应无明显影响。相反，L型VDCC拮抗剂硝苯地平在完全阻断KCl2反应的浓度下，仅抑制低氧引起的[Ca~(2+)](I)升高50%。灌流无钙KRBS可完全消除低氧引起的细胞内钙离子浓度升高。结论：急性低氧可通过激活SOCC而增强SOCE，导致远端PVSMC内[Ca+](I)升高。
Rationale: Exposure to acute hypoxia causes vasoconstriction in both pulmonary arteries (PA) and pulmonary veins (PV). The mechanisms on the arterial side have been studied extensively. However, bare attention has been paid to the venous side.Objectives: To investigate if acute hypoxia caused the increase of intracellular Ca2+ concentration ([Ca2+](i)), and Ca2+ influx through store-operated calcium channels (SOCC) in pulmonary venous smooth muscle cells (PVSMCs).Methods: Fluorescent microscopy and fura-2 were used to measure effects of 4% O-2 on [Ca2+](i) and store-operated Ca2+ entry (SOCE) in isolated rat distal PVSMCs.Measurements and main results: In PVSMCs perfused with Ca2+-free Krebs Ringer bicarbonate solution (KRBS) containing cyclopiazonic acid to deplete Ca2+ stores in the sarcoplasmic reticulum (SR) and nifedipine to prevent Ca2+ entry through L-type voltage-depended Ca2+ channels (VDCC), hypoxia markedly enhanced both the increase in [Ca2+](i) caused by restoration of extracellular [Ca2+] and the rate at which extracellular Mn2+ quenched fura-2 fluorescence. Moreover, the increased [Ca2+](i) in PVSMCs perfused with normal salt solution was completely blocked by SOCC antagonists SKF-96365 and NiCl2 at concentrations that SOCE >85% was inhibited but [Ca2+](i) responses to 60 mM KCl were not altered. On the contrary, L-type VDCC antagonist nifedipine inhibited increase in [Ca2+](i) to hypoxia by only 50% at concentrations that completely blocked responses to KCl. The increased [Ca2+](i) caused by hypoxia was completely abolished by perfusion with Ca2+-free KRBS.Conclusions: These results suggest that acute hypoxia enhances SOCE via activating SOCCs, leading to increased [Ca2+](i) in distal PVSMCs.