Serve G, Endres W, Grafe P
Physiologisches Institut der Universität München, Federal Republic of Germany.
Pflugers Arch. 1988 Apr;411(4):410-5. doi: 10.1007/BF00587720.
One type of ion-sensitive micro-electrode (K+ ligand Corning 477317) is sensitive to large quaternary ammonium ions such as choline or tetramethylammonium (TMA+). We have now used such electrodes for continuous electrophysiological measurements of changes in cell volume of motoneurons in the isolated frog spinal cord. The electrodes were double-barrelled with tip diameters of 1 micron. The reference barrel was filled with 100 mM choline or 100 mM TMA+ in 1 M Mg2+-acetate, the sensitive barrel contained the Corning K+ ligand. After the impalement of a motoneuron, choline or TMA+ diffused into the cell and about 1 h later, a steady-state concentration of these ions in the range of 10-20 mM was reached. Following this period, the motoneurons were activated by repetitive electrical stimulation or by application of amino acids via the bathing solution. All these stimuli led to a transient rise of the intracellular concentrations of choline or TMA+ (indicating a cell shrinkage of 3-10% difference to control volume).
一种离子敏感微电极（钾离子配体康宁477317）对诸如胆碱或四甲基铵（TMA+）等大型季铵离子敏感。我们现在已使用此类电极对分离的蛙脊髓中运动神经元的细胞体积变化进行连续电生理测量。电极是双管的，尖端直径为1微米。参比管中填充有1 M乙酸镁中的100 mM胆碱或100 mM TMA+，敏感管中含有康宁钾离子配体。刺入运动神经元后，胆碱或TMA+扩散到细胞中，约1小时后，这些离子的稳态浓度达到10 - 20 mM范围。在此之后，通过重复电刺激或经由浴液施加氨基酸来激活运动神经元。所有这些刺激均导致细胞内胆碱或TMA+浓度短暂升高（表明细胞收缩，与对照体积相差3 - 10%）。
