Lee C O, Armstrong W M
Science. 1972 Mar 17;175(4027):1261-4. doi: 10.1126/science.175.4027.1261.
Intracellular molar Na(+) activity (a(Na)), measured with cation-selective glass microelectrodes, in epithelial cells of isolated bullfrog small intestine immersed at 26 degrees C in a sodium sulfate Ringer solution containing mannitol was 0.0144 +/- 0.0031 (average value plus or minus standard deviation). The corresponding K(+) activity (a(K)) was 0.0854 +/- 0.0060. Combination of these values with previous estimates of intracellular Na(+) and K(+) concentrations under identical conditions indicated that a substantial fraction of the cellular Na(+) is in an osmotically inactive state. When the cells were exposed to a Ringer solution in which 26 millimoles of mannitol per liter were replaced by 3-O-methyl glucose, highly significant decreases in a(K) and a(Na) were observed. The decrease in a(K) was proportionately larger than the corresponding decrease in a(Na).
用阳离子选择性玻璃微电极测量，在26℃下浸于含甘露醇的硫酸钠林格溶液中的离体牛蛙小肠上皮细胞内的摩尔钠活性（a(Na)）为0.0144±0.0031（平均值±标准差）。相应的钾活性（a(K)）为0.0854±0.0060。将这些值与相同条件下先前对细胞内钠和钾浓度的估计相结合表明，细胞内相当一部分钠处于渗透非活性状态。当细胞暴露于每升26毫摩尔甘露醇被3 - O - 甲基葡萄糖替代的林格溶液中时，观察到a(K)和a(Na)显著降低。a(K)的降低比例大于相应的a(Na)降低比例。
