Inhibition of glutamate-induced delayed calcium deregulation by 2-APB and La3+ in cultured cortical neurones
Inhibition of glutamate-induced delayed calcium deregulation by 2-APB and La3+ in cultured cortical neurones
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DOI：
10.1111/j.1471-4159.2004.02732.x
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发表时间：
2004-10-01
影响因子：
4.7
通讯作者：
Adam-Vizi, V
中科院分区：
文献类型：
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作者：
Chinopoulos, C;Gerencser, AA;Adam-Vizi, V
培养的神经元暴露于谷氨酸的兴奋性毒性水平会导致细胞内[Ca~(2+)](I)最初的瞬时峰值，随后是一种延迟的、不可逆转的[Ca~(2+)](I)升高，这是由快速动力学控制的，其中Ca~(2+)来自细胞外培养液。继发性钙升高的分子机制尚不清楚。在这里，我们报告了2-氨基乙氧基二苯基硼酸盐(2-APB：IC50=62+/-9um)和La3+(IC50=7.2+/-3um)减少皮层神经元延迟的钙进入，这两种已知的抑制瞬时受体电位(TRP)和存储操作的钙离子(SOC)通道。然而，应用thapsigargin未能加剧延迟的Ca~(2+)解除调节，反对将储备物耗尽事件作为诱导次级[Ca~(2+)](I)升高的刺激。此外，这些神经元没有表现出SOC进入。出乎意料的是，兰诺定或咖啡因的应用显著抑制了谷氨酸诱导的延迟钙释放。在基础Ca~(2+)内流实验中，La~(3+)和2-APB可调节神经元在无钙介质中预先孵育后暴露于Ca~(2+)所引起的[Ca~(2+)](I)的快速升高。这种基础钙内流可被细胞外的镁离子缓解，但不会被塔普西林、兰尼定或咖啡因加重。这些结果表明，2-APB和La3+影响皮层神经元非钙库操作的钙内流，这种钙内流途径参与了谷氨酸诱导的延迟性钙释放。
Exposure of neurones in culture to excitotoxic levels of glutamate results in an initial transient spike in [Ca2+](i) followed by a delayed, irreversible [Ca2+](i) rise governed by rapid kinetics, with Ca2+ originating from the extracellular medium. The molecular mechanism responsible for the secondary Ca2+ rise is unknown. Here, we report that the delayed Ca2+ entry in cortical neurones is diminished by 2-aminoethoxydiphenyl borate (2-APB: IC50 = 62 +/- 9 muM) and La3+ (IC50 = 7.2 +/- 3 muM), both known to inhibit transient receptor potential (TRP) and store-operated Ca2+ (SOC) channels. Application of thapsigargin, however, failed to exacerbate the delayed Ca2+ deregulation, arguing against a store depletion event as the stimulus for induction of the secondary [Ca2+](i) rise. In addition, these neurones did not exhibit SOC entry. Unexpectedly, application of ryanodine or caffeine significantly inhibited glutamate-induced delayed Ca2+ deregulation. In basal Ca2+ entry experiments, La3+ and 2-APB modulated the rapid rise in [Ca2+](i) caused by exposure of neurones to Ca2+ after pre-incubating in a calcium-free medium. This basal Ca2+ influx was mitigated by extracellular Mg2+ but not aggravated by thapsigargin, ryanodine or caffeine. These results indicate that 2-APB and La3+ influence non-store-operated Ca2+ influx in cortical neurones and that this route of Ca2+ entry is involved in glutamate-induced delayed Ca2+ deregulation.