Institut de Physiologie et Biologie Cellulaires, UMR 6187, CNRS/Université de Poitiers, 40 avenue du Recteur Pineau, Poitiers, France.
Pflugers Arch. 2010 Jun;460(1):77-86. doi: 10.1007/s00424-010-0801-9. Epub 2010 Mar 5.
Na(v)1.6 is the major voltage-gated sodium channel at nodes of Ranvier. This channel has been shown to produce a robust persistent inward current in whole-cell experiments. Na(v)1.6 plays an important role in axonal conduction and may significantly contribute to the pathophysiology of the injured nervous system through this persistent current. However, the underlying molecular mechanisms and regulation of the persistent current are not well understood. Using the whole-cell configuration of the patch-clamp technique, we investigated the Na(v)1.6 transient and persistent currents in HEK-293. Previous studies have shown that the persistent current depended on the content of the patch electrode. Therefore, we characterised the single-channel properties of the persistent current with an intact intracellular medium using the cell-attached configuration of the patch-clamp technique. In HEK-293 cells, the Na(v)1.6 persistent current recorded in the whole-cell configuration was 3-5% of the peak transient current. In single-channel recording, the ratio between peak and persistent open probability confirmed the magnitude of the persistent current observed in the whole-cell configuration. The cell-attached configuration revealed that the molecular mechanism of the whole-cell persistent current is a consequence of single Na(v)1.6 channels reopening.
Nav1.6 是郎飞结处的主要电压门控钠离子通道。在全细胞实验中，该通道已被证明能产生强烈的持续内向电流。Nav1.6 在轴突传导中起着重要作用，通过这种持续电流，它可能对受损神经系统的病理生理学产生重大影响。然而，持续电流的潜在分子机制和调节仍不清楚。本研究采用膜片钳全细胞记录技术，研究了 HEK-293 中 Nav1.6 的瞬态和持续电流。先前的研究表明，持续电流取决于膜片电极的内容物。因此，我们使用膜片钳细胞贴附记录技术，在完整的细胞内环境中，对持续电流的单通道特性进行了研究。在 HEK-293 细胞中，全细胞记录的 Nav1.6 持续电流为峰值瞬态电流的 3-5%。在单通道记录中，峰值和持续开放概率之间的比值证实了全细胞记录中观察到的持续电流的幅度。细胞贴附记录显示，全细胞持续电流的分子机制是单个 Nav1.6 通道重新开放的结果。
