Laminar analysis of initiation and spread of epileptiform discharges in three in vitro models
Laminar analysis of initiation and spread of epileptiform discharges in three in vitro models
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DOI：
10.1016/j.brainresbull.2005.11.018
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发表时间：
2006-03-31
影响因子：
3.8
通讯作者：
Világi, I
中科院分区：
文献类型：
--
作者：
Borbély, S;Halasy, K;Világi, I
某些前脑结构中神经元网络的过度兴奋和神经元活动的病理同步化在癫痫发作中起着至关重要的作用。不同的惊厥剂可以通过实验引起癫痫发作。由于兴奋性和抑制性连接在新皮层的分布不同，癫痫发作敏感性可能存在层间差异。本实验用16通道多电极记录4-氨基吡啶、荷包牡丹碱和无镁溶液诱发的大鼠癫痫发作间期躯体感觉皮层不同层的癫痫样活动，并计算CSD。应用平行的c-Fos免疫细胞化学，每种惊厥剂引起特征性激活模式。4-氨基吡啶诱导的放电时间相对较短，与第V层的巨大汇有关，汇和源模式相对简单。无Mg（2+）溶液引起的最长的放电，这是与一个颗粒上的层II和III比迅速分布到层V和VI。荷包牡丹碱诱发的癫痫发作模式与无镁溶液相似，但场电位幅值较大，持续时间较短。然而，c-Fos激活的峰值与最大电激活不平行。4-氨基吡啶和荷包牡丹碱染色细胞分别出现在第II层和第III层。在无Mg（2+）的溶液中，在上层VI中检测到最高的c-Fos活性。持久的细胞效应并不总是对应于最大的电反应，这主要是由非对称锥体神经元的激活决定的。中间神经元，具有更多的对称过程分支，发挥不太重要的作用，在场电位的产生，虽然他们可能会强烈激活癫痫发作期间。(c)2005年爱思唯尔公司All rights reserved.
Overexcitation of neuronal networks in some forebrain structures and pathological synchronization of neuronal activity play crucial role in epileptic seizures. Seizure activity can be elicited experimentally by different convulsants. Because of various distribution of excitatory and inhibitory connections in the neocortex there might be laminar differences in seizure sensitivity. Current source density (CSD) analysis or immunocytochemical c-Fos localization offer suitable tools to localize increased activation of neurons during seizure.In the present experiments, interictal epileptiform activity elicited by 4-aminopiridine, bicuculline or Mg(2+)-free solution was recorded with a 16-channel multielectrode assembly in different layers of the somatosensory cortex, and CSDs were calculated. Parallel c-Fos immunocytochemistry was applied.Each convulsant elicited characteristic activation pattern. 4-Aminopiridine induced relatively short discharges, which were associated with a huge sink in layer V, the sink and source pattern was relatively simple. Mg(2+)-free solution elicited the longest discharges, which were associated with a supragranular layers II and III than quickly distributed toward layers V and VI. Bicuculline induced rather similar seizure pattern as Mg(2+)-free solution, but the amplitudes of field potentials were larger, while the durations shorter. The peak of c-Fos activation, however, was not parallel with the largest electrical activation. Larger amount of stained cells appeared in layers II and III in 4-aminopiridine and bicuculline, respectively. In Mg(2+)-free solution the highest c-Fos activity was detected in upper layer VI. Long-lasting cellular effects do not always correspond to the largest electrical responses, which are primarily determined by the activation of asymmetrical pyramidal neurons. Interneurons, which possess more symmetric process arborisation, play less important role in the generation of field potentials, although they may be intensively activated during seizure. (c) 2005 Elsevier Inc. All rights reserved.