Stewart R R, Bossu J L, Muzet M, Dupont J L, Feltz A
Laboratoire de Neurobiologie Cellulaire, UPR CNRS 9009 associée à l'Université Louis Pasteur, Strasbourg, France.
J Neurobiol. 1995 Dec;28(4):419-32. doi: 10.1002/neu.480280403.
The electrical properties of the precursor cells of the external germinal layer of rat cerebellum were assessed during their differentiation in control medium (Dulbecco's modified Eagle's medium) supplemented or not with either basic fibroblast growth factor (bFGF) or 25 mM potassium chloride (KCl). Resting potential was shown to be -10 mV in all three conditions 3 hours after plating [days in vitro (DIV)0]. By DIV 5, it reached -63 mV for cells cultured in 25 mM KCl but only -28 mV in control and bFGF media. The main voltage-sensitive ionic current measured at DIV 0 under all conditions was a composite IK consisting in a sustained K+ current blocked by tetraethylammonium (IK(TEA)), plus a rapidly activating and inactivating TEA-insensitive IK(A). Both currents increased with time in all conditions, but after 5 days IK(A) became dominant in terms of density. IK(TEA) is likely an IK(Ca), since it was blocked by 67% in 1 mM TEA. On DIV 0, INa and ICa were absent or small in amplitude. By DIV 3, 80% of the cells had currents able to generate a spike. Interestingly, ICa mean amplitude and current density measured at -10 mV in control condition on DIV 1 was significantly larger than those recorded in bFGF and 25 mM KCl. The order of appearance of the ionic currents, IK, ICa, and INa, leads directly to fast spike activity allowing for poor calcium entry. Firing rate likely depends on IK(A), which increased during the first 6 days of development but could be differentially regulated by bFGF.
在补充或未补充碱性成纤维细胞生长因子（bFGF）或25 mM氯化钾（KCl）的对照培养基（杜氏改良 Eagle 培养基）中，对大鼠小脑外颗粒层前体细胞在分化过程中的电特性进行了评估。接种3小时后（体外培养天数（DIV）0），在所有三种条件下静息电位均显示为-10 mV。到DIV 5时，在25 mM KCl中培养的细胞静息电位达到-63 mV，但在对照培养基和bFGF培养基中仅为-28 mV。在所有条件下，DIV 0时测量的主要电压敏感性离子电流是一种复合IK电流，由被四乙铵阻断的持续K+电流（IK(TEA)）加上快速激活和失活的对四乙铵不敏感的IK(A)电流组成。在所有条件下，两种电流均随时间增加，但5天后IK(A)在密度方面占主导地位。IK(TEA)可能是IK(Ca)，因为它在1 mM四乙铵中被阻断了67%。在DIV 0时，INa和ICa不存在或幅度较小。到DIV 3时，80%的细胞具有能够产生动作电位的电流。有趣的是，在DIV 1时对照条件下在-10 mV测量的ICa平均幅度和电流密度显著大于在bFGF和25 mM KCl中记录的值。离子电流IK、ICa和INa出现的顺序直接导致快速动作电位活动，使得钙内流较少。放电频率可能取决于IK(A)，IK(A)在发育的前6天增加，但可能受到bFGF的差异调节。
