Electrophysiological Characterization of Voltage-Dependent Potassium Channels in Human Neural Stem Cells

Abstract

Neural stem cells maybe allowed using in development of transplantation for treatment of neuronal disorders. This study has characterized the profile of membrane ion channels in cultured human neural stem cells using the patch clamp technique in the whole cell mode. In voltage clamp mode, the cells expressed both outward and inward rectifying K+ currents with no evidence for Na+ current. The outward delayed rectifying K+ current was activated by depolarization to potential more positive than -30 mV without inactivation and the reversal potential of this current was -54.1 mV, estimated from the observation of tail current. The inward rectifying K+ current was activated by hyperpolarization to potential more negative than -60 mV and this current had two kinetics including a fast inactivating instantaneous current and a steady state current according to time course of hyperpolarizing pulse. Both the outward and the inward K+ currents were blocked by 5 mM tetraethylammonium (TEA) in the same extent, but not by 2 mM 4-aminopyridine. It suggests that human neural stem cells have both outward and inward rectifying K+ currents and the characteristics of TEA-sensitive outward rectifying K+ currents without Na+ currents are similar to those of glial precursor or progenitor cells.