Synaptic interactions between pyramidal cells and interneurone subtypes during seizure-like activity in the rat hippocampus
Synaptic interactions between pyramidal cells and interneurone subtypes during seizure-like activity in the rat hippocampus
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DOI：
10.1113/jphysiol.2003.059915
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发表时间：
2004-06-15
影响因子：
5.5
通讯作者：
Takada, M
中科院分区：
文献类型：
--
作者：
Fujiwara-Tsukamoto, Y;Isomura, Y;Takada, M
我们最近报道，兴奋性GABA能和兴奋性GABA能机制可能参与产生类似癫痫发作的节律性同步（后放电），诱导在体外成熟大鼠海马CA 1区锥体细胞的强突触刺激。为了阐明这种神经元同步化的网络机制，双全细胞膜片钳记录的后放电反应进行了同时从各种interneurons和它们的相邻的锥体细胞在海马CA 1-分离的切片制备。根据形态学和电生理标准，记录的中间神经元，然后分为不同的亚型。位于腔隙分子层和放射层的非快速发放神经元在后放电过程中几乎不放电，而位于东方层和中间层的大多数快速发放和非快速发放神经元，包括篮状细胞、枝形细胞和双层细胞，表现出明显的放电，与锥体细胞的振荡反应精确同步。场电位记录表明，兴奋性突触传递可能主要发生在后放电的东方层和东方层。限制性病变的层oriens和delicale，而不是在其他层，导致完全deserminization后放电活动，而且，局部应用谷氨酸受体拮抗剂，这些层阻断后放电的表达。本研究结果提示，癫痫后放电的神经元同步化可能是通过兴奋性GABA能中间神经元与海马CA_1区的定向层和/或定向层内的海马锥体细胞形成的“正反馈回路”来完成的。
We have recently reported that excitatory GABAergic and glutamatergic mechanisms may be involved in the generation of seizure-like (ictal) rhythmic synchronization (afterdischarge), induced by a strong synaptic stimulation of the CA1 pyramidal cells in the mature rat hippocampus in vitro. To clarify the network mechanism of this neuronal synchronization, dual whole-cell patch-clamp recordings of the afterdischarge responses were performed simultaneously from a variety of interneurones and their neighbouring pyramidal cells in hippocampal CA1-isolated slice preparations. According to morphological and electrophysiological criteria, the recorded interneurones were then classified into distinct subtypes. The non-fast-spiking interneurones located in the strata lacunosum-moleculare and radiatum hardly discharged during the afterdischarge, whereas most of the fast-spiking and non-fast-spiking interneurones in the strata oriens and pyramidale, including the basket, chandelier and bistratified cells, exhibited prominent firings that were precisely synchronous with oscillatory responses in the pyramidal cells. Field potential recordings showed that excitatory synaptic transmissions might take place primarily in the strata oriens and pyramidale during the afterdischarge. Restricted lesions in the strata oriens and pyramidale, but not in the other layers, resulted in the complete desynchronization of afterdischarge activity, and also, local application of glutamate receptor antagonists to these layers blocked the expression of afterdischarge. The present findings indicate that the neuronal synchronization of epileptic afterdischarge may be accomplished in a 'positive feedback circuit' formed by the excitatory GABAergic interneurones and the glutamatergic pyramidal cells within the strata oriens and/or pyramidale of the hippocampal CA1 region.