title: Characterization of ionic currents in human neural stem cells.
abstract: 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.
authors: Department of Physiology, College of Medicine, Dankook University, Cheonan 330-714, Korea.
authors: Chae Gil
authors: CG
authors: Lim
authors: Sung-Soo
authors: SS
authors: Kim
authors: Haeyoung
authors: H
authors: Suh-Kim
authors: Young-Don
authors: YD
authors: Lee
authors: Seung Cheol
authors: SC
authors: Ahn