Guo Hong-Bo, Zou Fei
Department of Scientific Research, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China.
Zhonghua Yi Xue Za Zhi. 2008 Jan 15;88(3):179-84.
To explore the electrophysiological properties of outward voltage-gated potassium channels of neural stem cells (NSCs) from adult rat hippocampus.
NSCs were isolated from the hippocampus of adult SD rats with serum-free incubation and single-cell cloning technique. Immunochemistry technique was employed to identify the clone cells and clone cell-derived progeny. Electrophysiological recordings of various outward voltage-gated potassium channels were performed at room temperature using whole-cell patch clamp.
The floating neural spheres from the hippocampus showed the expression of nestin antigen, and were able to differentiate into neural cells expressing Yuj1 antigen and glial fibrillary acidic protein (GFAP) respectively in vitro. Three type specialized ion channels were find in cultured NSCs: The outward delayed rectifier outward K(+) currents (I(DR)) was characterized by a slow activation with depolarization and a sensitivity to tetraethylammonium (TEA). The current density of transient A type K(+) currents (I(A)) was 11 pA/pF +/- 3 pA/pF and 29 pA/pF +/- 7 pA/pF (n = 11) at +20 mV and +50 mV respectively, which was characterized by a rapid activation with depolarization and could be blocked by 4-AP. The large conductance calcium activated potassium (BKCa) channels was identified by the inhibition of iberiotoxin (IbTX). The current density of this channel at +80 mV was 56 pA/pF +/- 4 pA/pF and 45 pA/pF +/- 4 pA/pF (n = 6, P < 0.05) before and after application of 100 nM IbTX respectively.
The cultured NSCs of adult rat hippocampus express at least three kinds of outward voltage-gated potassium channels, I(DR), I(A), and BKCa in vitro.
探讨成年大鼠海马神经干细胞（NSCs）外向电压门控钾通道的电生理特性。
采用无血清培养和单细胞克隆技术从成年SD大鼠海马中分离神经干细胞。运用免疫化学技术鉴定克隆细胞及其衍生后代。在室温下使用全细胞膜片钳对各种外向电压门控钾通道进行电生理记录。
海马来源的悬浮神经球表达巢蛋白抗原，并且在体外能够分别分化为表达神经元特异性烯醇化酶（Yuj1）抗原的神经细胞和胶质纤维酸性蛋白（GFAP）。在培养的神经干细胞中发现了三种类型的特殊离子通道：外向延迟整流钾电流（I(DR)）的特征是随着去极化缓慢激活并对四乙铵（TEA）敏感。瞬时A型钾电流（I(A)）在+20 mV和+50 mV时的电流密度分别为11 pA/pF±3 pA/pF和29 pA/pF±7 pA/pF（n = 11），其特征是随着去极化快速激活并且可被4-氨基吡啶（4-AP）阻断。大电导钙激活钾（BKCa）通道通过iberiotoxin（IbTX）的抑制作用得以鉴定。在施加100 nM IbTX前后，该通道在+80 mV时的电流密度分别为56 pA/pF±4 pA/pF和45 pA/pF±4 pA/pF（n = 6，P < 0.05）。
成年大鼠海马培养的神经干细胞在体外至少表达三种外向电压门控钾通道，即I(DR)、I(A)和BKCa。
