Time course and mechanism of hippocampal neuronal death in an in vitro model of status epilepticus: Role of NMDA receptor activation and NMDA dependent calcium entry
Time course and mechanism of hippocampal neuronal death in an in vitro model of status epilepticus: Role of NMDA receptor activation and NMDA dependent calcium entry
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DOI：
10.1016/j.ejphar.2008.01.025
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发表时间：
2008-03-31
影响因子：
5
通讯作者：
DeLorenzo, Robert J.
中科院分区：
文献类型：
--
作者：
Deshpande, Laxmikant S.;Lou, Jeffrey K.;DeLorenzo, Robert J.
海马特别容易受到癫痫引起的损伤和兴奋性毒性神经元损伤。本研究采用低镁（Mg 2+）诱导海马神经元培养物中的连续高频癫痫样放电（体外癫痫持续状态），研究了神经元死亡与癫痫发作持续时间的关系以及癫痫诱导细胞死亡的药理学机制。使用细胞形态学和荧光素二乙酸盐-碘化丙啶染色评估神经元死亡。采用膜片钳电生理学方法评价了低Mg 2+和各种受体拮抗剂对峰电位频率的影响。我们观察到随着癫痫持续状态持续时间的增加，神经元死亡呈线性和时间依赖性增加。这种细胞死亡依赖于主要通过N-甲基-D-天冬氨酸（NMDA）谷氨酸受体通道亚型进入的细胞外钙（Ca 2+）。与NMDA受体拮抗剂共孵育，神经元死亡显着减少，也被抑制细胞外（Ca 2+）在癫痫持续状态。与此相反，在体外癫痫持续状态的神经元死亡并没有显着防止其他谷氨酸受体亚型或电压门控钙通道的抑制。有趣的是，与兴奋性毒性谷氨酸暴露引起的细胞死亡相比，这种NMDA-Ca 2+依赖性神经元死亡的发病更为缓慢。结果提供了证据表明，在体外癫痫持续状态的结果增加激活的NMDA-Ca 2+转导途径，导致神经元死亡的时间依赖性的方式。结果还表明，在持续癫痫发作活动的初始时间内，有一个重要的机会窗口，能够干预，保护神经元，降低与癫痫持续状态相关的高发病率和死亡率。(C)2008 Elsevier B. V.保留所有权利。
The hippocampus is especially vulnerable to seizure-induced damage and excitotoxic neuronal injury. This study examined the time course of neuronal death in relationship to seizure duration and the pharmacological mechanisms underlying seizure-induced cell death using low magnesium (Mg2+) induced continuous high frequency epileptiform discharges (in vitro status epilepticus) in hippocampal neuronal cultures. Neuronal death was assessed using cell morphology and fluorescein diacetate-propidium iodide staining. Effects of low Mg2+ and various receptor antagonists on spike frequency were assessed using patch clamp electrophysiology. We observed a linear and time-dependent increase in neuronal death with increasing durations of status epilepticus. This cell death was dependent upon extracellular calcium (Ca2+) that entered primarily through the N-methyl-D-aspartate (NMDA) glutamate receptor channel subtype. Neuronal death was significantly decreased by coincubation with the NMDA receptor antagonists and was also inhibited by reduction of extracellular (Ca2+) during status epilepticus. In contrast, neuronal death from in vitro status epilepticus was not significantly prevented by inhibition of other glutamate receptor subtypes or voltage-gated Ca2+ channels. Interestingly this NMDA-Ca2+ dependent neuronal death was much more gradual in onset compared to cell death from excitotoxic glutamate exposure. The results provide evidence that in vitro status epilepticus results in increased activation of the NMDA-Ca2+ transduction pathway leading to neuronal death in a time-dependent fashion. The results also indicate that there is a significant window of opportunity during the initial time of continuous seizure activity to be able to intervene, protect neurons and decrease the high morbidity and mortality associated with status epilepticus. (C) 2008 Elsevier B.V. All rights reserved.