Electric pulse stimulation induces NMDA glutamate receptor mRNA in NIH3T3 mouse fibroblasts
Electric pulse stimulation induces NMDA glutamate receptor mRNA in NIH3T3 mouse fibroblasts
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DOI：
10.1620/tjem.215.181
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发表时间：
2008-06-01
影响因子：
2.2
通讯作者：
Nagatomi, Ryoichi
中科院分区：
文献类型：
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作者：
Okutsu, Saeko;Hatakeyama, Hiroyasu;Nagatomi, Ryoichi
过量的谷氨酸和钙离子流入神经元加剧脑损伤，如缺血。损伤部位的星形胶质细胞通过n -甲基- d -天冬氨酸（NMDA）谷氨酸受体和l型Ca2+通道分别清除过量的谷氨酸和Ca2+，增殖和减弱谷氨酸和Ca2+诱导的神经元损伤。成纤维细胞通常被动员到损伤部位，可能支持修复过程。值得注意的是，成纤维细胞表达l型电压敏感Ca2+通道，但不表达中枢神经系统特异性NMDA谷氨酸受体。我们研究了电脉冲刺激（EPS）是否能够通过Ca2+通道激活诱导成纤维细胞上的NMDA受体，因此它们可能具有潜在的神经保护作用。为了激活l型Ca2+通道，我们向培养的NIH3T3小鼠成纤维细胞传递电脉冲。通过Fluo-4AM钙显像检测，20 V脉冲持续时间为2 msec，频率为1 Hz，持续时间超过1 h至24 h，成功地将Ca2+引入NIH3T3成纤维细胞中，并被l型Ca2+通道抑制剂维拉帕米完全抑制。RT-PCR结果显示，EPS 24h后成纤维细胞中NMDA受体mRNA表达显著。EPS期间维拉帕米完全消除了EPS诱导的NMDA受体mRNA的表达。据我们所知，这是第一个显示电脉冲能够通过非兴奋性成纤维细胞中的l型Ca2+通道诱导持续的Ca2+内流，从而导致cns特异性NMDA受体mRNA的表达的报告。NMDA受体对成纤维细胞的神经保护作用有待进一步研究。
Excess glutamate and Ca2+ influx into neurons exacerbate brain damage such as ischemia. Astrocytes at the site of damage proliferate and attenuate the glutamate- and Ca2+-induced neuronal damage by removing excess glutamate and Ca2+ through the N-methyl-D-aspartate (NMDA) glutamate receptor and the L-type Ca2+ channel, respectively. Fibroblasts are commonly mobilized to the site of damage, probably supporting the restoration process. Notably, fibroblasts express the L-type voltage-sensitive Ca2+ channel, but not central nervous system-specific NMDA glutamate receptor. We examined if electric pulse stimulation (EPS) was capable of inducing NMDA receptor on fibroblasts by way of Ca2+ channel activation, so that they could potentially have a neuroprotective role. To activate L-type Ca2+ channel, we delivered electric pulse to cultured NIH3T3 mouse fibroblasts. EPS of 20 V with a pulse duration of 2 msec at a frequency of 1 Hz for more than 1 h up to 24 h successfully introduced Ca2+ into NIH3T3 fibroblasts as detected by Fluo-4AM calcium imaging, which was totally inhibited by a L-type Ca2+ channel inhibitor, verapamil. Remarkable expression of NMDA receptor mRNA in the fibroblasts after 24-h EPS was demonstrated by RT-PCR. Verapamil treatment during EPS totally abrogated the EPS-induced NMDA receptor mRNA expression. To the best of our knowledge, this is the first report showing that electric pulse is able to induce sustained Ca2+ influx via L-type Ca2+ channel in a non-excitatory fibroblast, which leads to the expression CNS-specific NMDA receptor mRNA. Neuroprotective role of NMDA receptor induced in fibroblasts needs to be further examined.