Astrocyte dysfunction, and in particular impaired extracellular potassium spatial buffering, has been postulated to have a potential role in seizure susceptibility and ictogenesis. Inwardly rectifying potassium (Kir) channels, and specifically KIR4.1, have a predominant role in K⁺ homeostasis and their involvement in neuronal excitability control have been hypothesized. To avoid the severe side effects observed in Kir4.1 cKO, we studied the effects of Kir4.1 down-regulation in cortical astrocytes by using Kir4.1 RNA interference (RNAi) technique combined with in utero electroporation (IUE) at E16 and a piggyBac transposon system. Kir4.1 down-regulation was confirmed by immunohistochemistry and field fraction analysis. To investigate if Kir4.1 silencing affects 4AP–induced seizure threshold and extracellular potassium homeostasis, simultaneous in vitro field potential and extracellular K⁺ recordings were performed on somatosensory cortex slices obtained from rats electroporated with a piggyBac-Kir4.1-shRNA (Kir4.1⁻) and scrambled shRNA (Kir4.1^Sc). Electrophysiological data revealed no significant differences in terms of seizure onset and seizure-induced extracellular K⁺ changes between Kir4.1⁻ and Kir4.1^Sc rats. Intriguingly, immunohistochemical analysis performed on slices studied with electrophysiology revealed a reduced number of neurons generated from radial glial cells in Kir4.1⁻ rats.

We conclude that focal down-regulation of Kir4.1 channel in cortical astrocytes by Kir4.1 RNAi technique combined with IUE is not effective in altering potassium homeostasis and seizure susceptibility. This technique revealed a possible role of Kir4.1 during corticogenesis.

星形胶质细胞功能障碍，特别是受损的细胞外钾空间缓冲作用，已被假定在癫痫发作易感性和信息生成中具有潜在作用。向内整流的钾离子通道（Kir），特别是KIR4.1，在K ⁺稳态中起主要作用，并且推测它们参与神经元兴奋性控制。为避免在Kir4.1 cKO中观察到严重的副作用，我们通过使用Kir4.1 RNA干扰（RNAi）技术结合子宫内电穿孔（IUE）在E16和A16处研究了皮质星形胶质细胞中Kir4.1下调的作用。小猪转座子系统。免疫组织化学和视野分数分析证实了Kir4.1的下调。为了研究Kir4.1沉默是否影响4AP诱发的癫痫发作阈值和细胞外钾稳态，同时对从用piggyBac- Kir4.1- shRNA电穿孔的大鼠体内获得的体感皮层切片同时进行了体外场电势和细胞外K ⁺记录（Kir4。 1 ^{- ）}和乱序shRNA（KIR4.1^钪）。电数据痉挛发作和发作引起的细胞外钾方面没有发现显著差异⁺ KIR4.1之间的变化^-和KIR4.1^钪大鼠。有趣的是，与电生理学研究切片进行免疫组织化学分析揭示了从放射状胶质细胞中产生KIR4.1神经元数量的减少^-大鼠。

我们得出的结论是，通过Kir4.1 RNAi技术与IUE结合，皮质星形胶质细胞中Kir4.1通道的局灶性下调在改变钾稳态和癫痫发作易感性方面无效。这项技术揭示了在成皮质过程中Kir4.1的可能作用。