Reichenbach A, Eberhardt W
Carl Ludwig Institute of Physiology, Karl Marx University, Leipzig, German Democratic Republic.
Glia. 1988;1(3):191-7. doi: 10.1002/glia.440010304.
Müller (radial glial) cells were isolated from rabbit retinae by means of papaine and mechanical dissociation. Regional membrane properties of these cells were studied by intracellular microelectrode recordings of potential responses to local application of high K+ solutions. When different parts of the cell membrane were exposed to high K+, the amplitude of the depolarizing responses varied greatly, indicating a strong regional specialization of the membrane properties. Using morphometrical data of isolated rabbit Müller cells, and a simple circuit model, we calculated the endfoot membrane to constitute more than 80% of the total K+ conductance of the cell; the specific resistivity of the endfoot membrane was about 400 omega cm2, i.e., more than 40 times less than that of the membrane of the vitread process, which is immediately adjacent. This kind of regional membrane specialization seems to be optimized in respect to the Müller cells' ability to carry spatial buffering K+ currents.
通过木瓜蛋白酶和机械分离法从兔视网膜中分离出米勒（放射状胶质）细胞。通过细胞内微电极记录局部应用高钾溶液时的电位反应，研究了这些细胞的局部膜特性。当细胞膜的不同部分暴露于高钾时，去极化反应的幅度变化很大，表明膜特性存在强烈的局部特化。利用分离的兔米勒细胞的形态测量数据和一个简单的电路模型，我们计算出终足膜构成细胞总钾电导的80%以上；终足膜的比电阻率约为400Ω·cm²，即比紧邻的玻璃体突起膜的比电阻率小40倍以上。就米勒细胞传导空间缓冲钾电流的能力而言，这种局部膜特化似乎是优化的。
