Francis J, Jugloff D G, Mingo N S, Wallace M C, Jones O T, Burnham W M, Eubanks J H
The Toronto Hospital, Western Division, Ontario, Canada.
Neurosci Lett. 1997 Aug 29;232(2):91-4. doi: 10.1016/s0304-3940(97)00593-4.
Potassium channels play a key role in the regulation of membrane excitability. We investigated the gene expression response of the Kv4.2 subtype of potassium channel, in the rat hippocampus, to a brief (5 min) episode of kainic acid-induced seizures. Our results demonstrate that Kv4.2 expression is reduced in the granule cell layer of the dentate gyrus at 3 h post-seizure, while no significant changes in expression are observed in other hippocampal subfields. At 6 h post-challenge, expression in both dentate hilar cells and granule cells is reduced, while no other significant changes are observed. At 24 h post-challenge, expression levels for Kv4.2 in the dentate granule cells have rebounded to levels greater than control, while expression levels are significantly reduced in the CA3 and CA4 subfields. No significant changes in Kv4.2 expression are observed in kainic acid-administered animals that fail to seize, indicating that the changes in gene expression result from seizure activity and not from the direct actions of the administered kainic acid. These results demonstrate that brief kainic acid-induced epileptiform activity promotes alterations in the expression levels for the Kv4.2 subtype of potassium channel gene.
钾通道在调节膜兴奋性方面发挥着关键作用。我们研究了大鼠海马体中钾通道Kv4.2亚型对短暂（5分钟） kainic酸诱导癫痫发作的基因表达反应。我们的结果表明，癫痫发作后3小时，齿状回颗粒细胞层中Kv4.2表达降低，而在其他海马亚区未观察到表达的显著变化。攻击后6小时，齿状门区细胞和颗粒细胞中的表达均降低，而未观察到其他显著变化。攻击后24小时，齿状颗粒细胞中Kv4.2的表达水平已反弹至高于对照的水平，而CA3和CA4亚区的表达水平显著降低。在未发生癫痫发作的给予kainic酸的动物中未观察到Kv4.2表达的显著变化，这表明基因表达的变化是由癫痫活动引起的，而不是由给予的kainic酸的直接作用引起的。这些结果表明，短暂的kainic酸诱导的癫痫样活动促进了钾通道基因Kv4.2亚型表达水平的改变。
