Kettenmann H, Sonnhof U, Schachner M
J Neurosci. 1983 Mar;3(3):500-5. doi: 10.1523/JNEUROSCI.03-03-00500.1983.
Membrane potential, conductance, and intracellular potassium concentration were measured in oligodendrocytes in 3- to 10-week-old cultures of embryonic mouse spinal cord. After intracellular recording the cells were first injected with Lucifer Yellow and then stained by immunofluorescence using rhodamine-labeled monoclonal antibody 01 specific for oligodendrocyte cell surfaces. The membrane potential of these identified oligodendrocytes was in mV -66 +/- 4.3 SD; it could be reversibly reduced almost to zero by the addition of ouabain. Changes in external K+ but not Na+, Ca++, or Cl- changed the membrane potential. A 10-fold increase in extracellular potassium concentration ([K+]0) depolarized the cell by about 52 mV. This is less than the 61 mV predicted by the Nernst equation for a K+ electrode assuming a constant intracellular potassium concentration ([K+]i). However, when [K+]i was measured with an ion-selective electrode during the increase in [K+]0 it was found to rise. The Nernst equation for K+ accurately predicts the oligodendrocyte membrane potential when the increase in [K+]i is taken into account. Oligodendrocytes may be described as accurate K+ electrodes with a variable reference solution.
在3至10周龄的胚胎小鼠脊髓培养物中的少突胶质细胞中测量膜电位、电导和细胞内钾浓度。在进行细胞内记录后，首先向细胞内注入荧光黄，然后使用针对少突胶质细胞表面的罗丹明标记单克隆抗体01通过免疫荧光进行染色。这些已鉴定的少突胶质细胞的膜电位为-66±4.3 SD（毫伏）；加入哇巴因后，膜电位可几乎可逆地降至零。细胞外K⁺而非Na⁺、Ca²⁺或Cl⁻的变化会改变膜电位。细胞外钾浓度（[K⁺]₀）增加10倍会使细胞去极化约52毫伏。这低于能斯特方程预测的假设细胞内钾浓度（[K⁺]ᵢ）恒定的钾电极的61毫伏。然而，当在[K⁺]₀增加期间用离子选择性电极测量[K⁺]ᵢ时，发现其升高。当考虑到[K⁺]ᵢ的增加时，钾的能斯特方程能准确预测少突胶质细胞的膜电位。少突胶质细胞可被描述为具有可变参比溶液的精确钾电极。
