Hoffman W H, Haberly L B
Neuroscience Training Program, University of Wisconsin, Madison 53706.
J Neurosci. 1991 Jul;11(7):2021-31. doi: 10.1523/JNEUROSCI.11-07-02021.1991.
Previous study revealed that bursting activity generated by a variety of means in slices of piriform cortex induces persistent epileptiform EPSPs in superficial pyramidal cells by an NMDA-dependent process. The present study was undertaken to test the hypothesis that the observed epileptiform EPSPs in superficial pyramidal cells are driven by deep cells. This hypothesis was suggested by recent findings from in vitro studies of the properties of deep cells and in vivo studies indicating that the deep part of the piriform cortex or neighboring deep structures are involved in the generation of seizure activity in animal models of epilepsy. Results from simultaneous cell-pair recordings, examination of subdivided slices, and local application of excitatory and inhibitory agents provided strong evidence in support of this hypothesis. It was concluded that the endopiriform nucleus, a collection of cells immediately deep to the piriform cortex, plays a central role in generation, but that cells in the deep part of layer III and the claustrum may also contribute. Furthermore, it was found that generation of prolonged ictal-like activity only occurs in slices of piriform cortex in which the endopiriform nucleus is present. Implications of these findings for epileptogenesis are discussed.
先前的研究表明，在梨状皮质切片中通过多种方式产生的爆发性活动，通过一种依赖N-甲基-D-天冬氨酸（NMDA）的过程，在浅层锥体细胞中诱导出持续性癫痫样兴奋性突触后电位（EPSP）。本研究旨在检验以下假设：在浅层锥体细胞中观察到的癫痫样EPSP是由深层细胞驱动的。近期关于深层细胞特性的体外研究以及体内研究结果提示了这一假设，这些研究表明梨状皮质深部或邻近的深部结构参与癫痫动物模型中癫痫活动的产生。同时进行的细胞对记录、对分割切片的检查以及局部应用兴奋性和抑制性药物的结果，为支持这一假设提供了有力证据。得出的结论是，梨状皮质内梨状核（紧位于梨状皮质深部的一群细胞）在其产生过程中起核心作用，但第三层深部的细胞和屏状核也可能有贡献。此外，还发现只有在存在梨状皮质内梨状核的梨状皮质切片中才会产生持续的癫痫样活动。讨论了这些发现对癫痫发生的意义。
