Department of Physiology, College of Medicine, Dankook University, Cheonan 330-714, Korea.
Korean J Physiol Pharmacol. 2008 Aug;12(4):131-5. doi: 10.4196/kjpp.2008.12.4.131. Epub 2008 Aug 31.
The profile of membrane currents was investigated in differentiated neuronal cells derived from human neural stem cells (hNSCs) that were obtained from aborted fetal cortex. Whole-cell voltage clamp recording revealed at least 4 different currents: a tetrodotoxin (TTX)-sensitive Na(+) current, a hyperpolarization-activated inward current, and A-type and delayed rectifier-type K(+) outward currents. Both types of K(+) outward currents were blocked by either 5 mM tetraethylammonium (TEA) or 5 mM 4-aminopyridine (4-AP). The hyperpolarization-activated current resembled the classical K(+) inward current in that it exhibited a voltage-dependent block in the presence of external Ba(2+) (30microM) or Cs(+) (3microM). However, the reversal potentials did not match well with the predicted K(+) equilibrium potentials, suggesting that it was not a classical K(+) inward rectifier current. The other Na(+) inward current resembled the classical Na(+) current observed in pharmacological studies. The expression of these channels may contribute to generation and repolarization of action potential and might be regarded as functional markers for hNSCs-derived neurons.
研究了从流产胎儿皮层中获得的人神经干细胞 (hNSC) 分化的神经元细胞中的膜电流特征。全细胞电压钳记录显示至少有 4 种不同的电流：河豚毒素 (TTX) 敏感的 Na(+) 电流、超极化激活内向电流以及 A 型和延迟整流型 K(+) 外向电流。两种类型的 K(+) 外向电流均被 5 mM 四乙铵 (TEA) 或 5 mM 4-氨基吡啶 (4-AP) 阻断。超极化激活电流类似于经典的 K(+) 内向电流，因为它在存在外部 Ba(2+) (30μM) 或 Cs(+) (3μM) 时表现出电压依赖性阻断。然而，反转电位与预测的 K(+) 平衡电位不太吻合，表明它不是经典的 K(+) 内向整流电流。另一种 Na(+) 内向电流类似于药理学研究中观察到的经典 Na(+) 电流。这些通道的表达可能有助于动作电位的产生和复极化，并可能被视为 hNSC 衍生神经元的功能标志物。
