Department of Physiology at the Institute of Basal Medical Sciences, University of Oslo, 0317 Oslo, Norway.
Department of Physiology at the Institute of Basal Medical Sciences, University of Oslo, 0317 Oslo, Norway
J Neurosci. 2014 May 14;34(20):6807-12. doi: 10.1523/JNEUROSCI.4153-13.2014.
The medial entorhinal cortex (MEC) is important for spatial navigation and memory. Stellate cells (SCs) of MEC layer II provide major input to the hippocampus, and are thought to be the neuronal correlate of the grid cells. Their electrophysiological properties have been used to explain grid field formation. However, little is known about the functional roles of potassium channels in SCs. M-current is a slowly activating potassium current, active at subthreshold potentials. Although some studies have suggested that Kv7/M-channels may affect subthreshold resonance in SCs, others have found no Kv7/M-current in these cells, so the expression and roles of Kv7/M-channels in SCs are still debated. Using whole-cell voltage-clamp, we have identified a typical M-current with pharmacological properties characteristic of Kv7/M-channels in rat MEC SCs. Current-clamp experiments showed that the specific Kv7/M-channel blocker XE991 increased SCs excitability, and reduced spike frequency adaptation. Our results demonstrate that Kv7/M-channels are expressed in SCs and contribute substantially to regulation of excitability in these cells.
内侧缰状回皮层（MEC）在空间导航和记忆中起重要作用。MEC 层 II 的星状细胞（SCs）向海马提供主要输入，被认为是网格细胞的神经元相关性。它们的电生理特性被用于解释网格场的形成。然而，钾通道在SCs 中的功能作用知之甚少。M 电流是一种在亚阈电位下激活的缓慢激活钾电流。尽管一些研究表明 Kv7/M 通道可能影响 SCs 中的亚阈共振，但其他研究并未在这些细胞中发现 Kv7/M 电流，因此 Kv7/M 通道在 SCs 中的表达和作用仍存在争议。通过全细胞膜片钳技术，我们在大鼠 MEC SCs 中鉴定出一种具有 Kv7/M 通道特征的典型 M 电流。电流钳实验表明，特异性 Kv7/M 通道阻断剂 XE991 增加了SCs 的兴奋性，并降低了尖峰频率适应。我们的研究结果表明，Kv7/M 通道在 SCs 中表达，并对这些细胞的兴奋性调节有重要贡献。
