Physiologic electrical stimulation provokes intracellular calcium increase mediated by phospholipase C activation in human osteoblasts
Physiologic electrical stimulation provokes intracellular calcium increase mediated by phospholipase C activation in human osteoblasts
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DOI：
10.1096/fj.04-1814fje
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发表时间：
2004-09-01
期刊：
影响因子：
4.8
通讯作者：
Cho, M
中科院分区：
文献类型：
--
作者：
Khatib, L;Golan, DE;Cho, M
强的外源性电刺激（ES）可引起细胞内钙离子浓度（[Ca ~（2+）]（i））的变化。然而，仍有待阐明的是，生理相关的ES（例如，1-2 V/cm）可改变[Ca ~（2+）]（i）。我们使用荧光显微镜来量化人胎儿成骨细胞中[Ca 2 +]（i）响应直流电（dc）ES的变化。响应于2 V/cm ES的[Ca 2 +]（i）的增加显示出明显的（20分钟）时间延迟，随后从基线40 nM增加45倍至1.8 μ M。用维拉帕米处理细胞不影响ES诱导的[Ca 2 +]（i）增加，但抑制磷脂酶C（PLC）确实阻止了这种增加，这表明可能涉及受体调节的细胞内储存的Ca 2+释放。用牵张激活阳离子通道（SACC）阻断剂Gd 3+处理细胞部分抑制ES诱导的[Ca 2 +]（i）增加，细胞内Ca 2+的螯合作用也是如此。这些结果与生理学相关ES不直接激活电压门控Ca 2+通道（VGCC），而是刺激PLC偶联的细胞表面受体的模型一致，PLC偶联的细胞表面受体通过激活IP 3依赖性细胞内过程诱导[Ca 2 +]（i）增加。PLC激活后的Ca 2+内流可能由机械操作的SACC的激活介导。
Strong exogenous electrical stimulation (ES) can induce changes in intracellular calcium ion concentration ([Ca2+](i)). It remains to be elucidated, however, whether physiologically relevant ES (e.g., 1-2 V/cm) could alter [Ca2+](i). We have used fluorescence microscopy to quantify [Ca2+](i) changes in response to direct current (dc) ES in human fetal osteoblasts. Increases in [Ca2+](i) in response to 2 V/cm ES show a noticeable (20-min) time delay, followed by a 45-fold rise from the baseline of 40 nM to 1.8 muM. Treatment of cells with verapamil does not affect ES-induced [Ca2+](i) increases, but inhibition of phospholipase C ( PLC) does prevent such increases, which suggests that receptor-regulated release of Ca2+ from intracellular stores is likely to be involved. Treatment of cells with the stretch-activated cation channel (SACC) blocker Gd3+ partially inhibits ES-induced [Ca2+](i) increases, as does chelation of intracellular Ca2+. These results are consistent with a model in which physiologically relevant ES does not activate voltage-gated Ca2+ channels (VGCCs) directly, but rather stimulates PLC-coupled cell surface receptors that induce [Ca2+](i) increases by activating IP3-dependent intracellular processes. The Ca2+ influx that follows PLC activation is likely mediated by activation of mechanically operated SACCs.