Huba R, Schneider H, Hofmann H D
Max-Planck-Institut für Hirnforschung, Frankfurt, F.R.G.
Brain Res. 1992 Apr 10;577(1):10-8. doi: 10.1016/0006-8993(92)90531-d.
To analyze the voltage-dependent ionic conductances of putative GABAergic amacrine cells developing in vitro, whole cell patch clamp recordings were carried out on identified neurons in monolayer cultures from embryonic chick retinae. These recordings were directly compared with those performed on amacrine cells in chick retinal slice preparations. Current responses to depolarizing voltage steps observed in cultured neurons could be separated into at least four different components. A small tetrodotoxin-sensitive sodium inward current was observed in approximately 50% of the cells. The considerably larger outward potassium current consisted of a transient 4-aminopyridine-sensitive component and a sustained component. The latter was reduced in the presence of both tetraethylammonium chloride and Co2+ and thus was probably composed of two conductances. In addition, a Ca(2+)-carried inward current of small amplitude could be identified. Voltage-sensitive currents measured in amacrine cells of retinal slices were very similar. Again, only about half of the cells exhibited sodium currents. Potassium currents contained the above components, but their contributions to the whole cell current seemed to be different. Together with previous findings these results suggest that immature retinal neurons in dissociated cultures undergo a differentiation process similar to that occurring in vivo.
为了分析体外培养的假定GABA能无长突细胞的电压依赖性离子电导，对来自胚胎鸡视网膜的单层培养物中的已鉴定神经元进行了全细胞膜片钳记录。这些记录直接与在鸡视网膜切片制备物中的无长突细胞上进行的记录进行比较。在培养的神经元中观察到的对去极化电压阶跃的电流反应可分为至少四个不同的成分。在大约50%的细胞中观察到一种小的河豚毒素敏感的钠内向电流。相当大的外向钾电流由一个短暂的4-氨基吡啶敏感成分和一个持续成分组成。后者在氯化四乙铵和Co2+同时存在时减小，因此可能由两种电导组成。此外，可以识别出一个小幅度的Ca(2+)携带的内向电流。在视网膜切片的无长突细胞中测量的电压敏感电流非常相似。同样，只有大约一半的细胞表现出钠电流。钾电流包含上述成分，但它们对全细胞电流的贡献似乎不同。与先前的发现一起，这些结果表明，解离培养中的未成熟视网膜神经元经历了与体内发生的过程相似的分化过程。
