Measurements of mitochondrial pH in cultured cortical neurons clarify contribution of mitochondrial pore to the mechanism of glutamate-induced delayed Ca2+ deregulation
Measurements of mitochondrial pH in cultured cortical neurons clarify contribution of mitochondrial pore to the mechanism of glutamate-induced delayed Ca2+ deregulation
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DOI：
10.1016/j.ceca.2007.10.005
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发表时间：
2008-06-01
期刊：
影响因子：
4
通讯作者：
Khodorov, Boris I.
中科院分区：
文献类型：
--
作者：
Bolshakov, Alexey P.;Mikhailova, Maria M.;Khodorov, Boris I.
为了阐明线粒体通透性转换孔（MPT）在谷氨酸诱导的延迟性钙失调（DCD）和线粒体去极化（MD）机制中的作用，我们研究了谷氨酸诱导表达pH敏感荧光蛋白的培养皮层神经元胞浆pH（m）和线粒体pH（c）的变化。我们发现DCD和MD与显著的pH（m）降低相关，这可能是MPT开放所致。这种pH值（m）降低发生在DCD和MD发作后一定时间内。这反驳了MPT开放在DCD触发中起主导作用的假设。用MPT开放拮抗剂Sr ~（2+）替代Ca ~（2+）的实验也支持了这一结论。我们发现，在含Sr 2+的培养基中，谷氨酸诱导的延迟锶失调（DSD），类似于DCD，这是伴随着深刻的MD。与DSD相关的pH（c）和pH（m）的变化的分析使我们得出结论，含Sr 2+的介质中的MD在不涉及孔的情况下发生。相反，在含Ca 2+的介质中，这种“非孔机制”只负责MD的启动，而在MD发展的最后阶段，MPT发挥了重要作用。(C)2007爱思唯尔有限公司保留所有权利。
To clarify the role of the mitochondrial permeability transition pore (MPT) in the mechanism of the glutamate-induced delayed calcium deregulation (DCD) and mitochondrial depolarization (MD), we studied changes in cytosolic (pH(m)) and mitochondrial pH (pH(c)) induced by glutamate in cultured cortical neurons expressing pH-sensitive fluorescent proteins. We found that DCD and MD were associated with a prominent pH(m) decrease which presumably resulted from MPT opening. This pH(m) decrease occurred with some delay after the onset of DCD and MD. This argued against the hypothesis that MPT opening plays a dominant role in triggering of DCD. This conclusion was also supported by experiments in which Ca2+ was replaced with antagonist of MPT opening Sr2+. We found that in Sr2+-containing medium glutamate-induced delayed strontium deregulation (DSD), similar to DCD, which was accompanied by a profound MD. Analysis of the changes in pH(c) and pH(m) associated with DSD led us to conclude that MD in Sr2+-containing medium occurred without involvement of the pore. In contrast, in Ca2+-containing medium such "non-pore mechanism" was responsible only for MD initiation while in the final stages of MD development the MPT played a major role. (C) 2007 Elsevier Ltd. All rights reserved.