Ca2+ signalling and changes of mitochondrial function during low-Mg2+-induced epileptiform activity in organotypic hippocampal slice cultures
Ca2+ signalling and changes of mitochondrial function during low-Mg2+-induced epileptiform activity in organotypic hippocampal slice cultures
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DOI：
10.1046/j.0953-816x.2001.01505.x
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发表时间：
2001-04-01
影响因子：
3.4
通讯作者：
Heinemann, U
中科院分区：
文献类型：
--
作者：
Kovacs, R;Schuchmann, S;Heinemann, U
一些证据表明，神经元活动的增强与线粒体功能的增加有关，然而，耦合的机制仍不清楚。在这项研究中，我们使用低细胞外Mg2+浓度和短时间刺激训练，在海马切片培养中以癫痫样事件（SLE）的形式引起神经元亢进。同时应用微荧光和电生理技术来深入了解Ca2+浓度在不同室室的变化和线粒体功能。SLEs与细胞外Ca2+浓度（[Ca2+]e）的大幅下降，细胞质的急剧增加和线粒体Ca2+浓度（细胞质浓度[Ca2+]i；线粒体内浓度[Ca2+]m）的平缓升高有关。在线粒体膜电位（δ Psi）和NAD(P)H自身荧光最初明显下降后，线粒体去极化和NADH产生增加。此外，SLEs与二氢乙胺（HEt）氧化增加有关。我们的数据表明，线粒体内Ca2+积累刺激NADH的产生和自由基氧（ROS）的产生。有趣的是，线粒体去极化随[Ca2+]i和[Ca2+]m的变化而延迟，这意味着从线粒体基质中挤出Ca2+可能是线粒体膜去极化的原因。
Several lines of evidence indicate that augmented neuronal activity is associated with increased mitochondrial function, however, the mechanisms of coupling are still unclear. In this study we used a low extracellular Mg2+ concentration and short stimulus trains to evoke neuronal hyperactivity in the form of seizure-like events (SLE) in hippocampal slice cultures. Simultaneous microfluorimetric and electrophysiological techniques were applied to gain insight into changes of Ca2+ concentration in different compartments and into mitochondrial function. SLEs were associated with a large decrease of the extracellular Ca2+ concentration ([Ca2+]e), a spiking increase of the cytoplasmic and a smoothed elevation of the mitochondrial Ca2+ concentration (cytoplasmic concentration [Ca2+]i; intramitrochondrial concentration [Ca2+]m). Following an initial apparent decline in the mitochondrial membrane potential (Delta Psi) and NAD(P)H autofluorescence, mitochondria depolarized and NADH production was augmented. Furthermore, SLEs were associated with increased oxidation of dihydroethidine (HEt). Our data Suggest that intramitochondrial Ca2+ accumulation stimulates NADH production and production of radical oxygen species (ROS). Interestingly, mitochondrial depolarization followed [Ca2+]i and [Ca2+]m changes with a delay implying that electrogenic extrusion of Ca2+ from the mitochondrial matrix might be responsible for the depolarization of the mitochondrial membrane.