Rick R, Dörge A, Macknight A D, Leaf A, Thurau K
J Membr Biol. 1978 Mar 10;39(2-3):257-71. doi: 10.1007/BF01870334.
The electrolyte composition of toad urinary bladder epithelial cells has been measured using the technique of electron microprobe analysis. Portions of hemibladders, which had been mounted in chambers and bathed with a variety of media, were layered with albumin solution on their mucosal surfaces and immediately shock-frozen in liquid propane at -180 degrees C. From the frozen material 1--2 micrometer thick cryosections were cut and promptly freeze-dried for 12 hr at-80 degrees C and 10(-6) Torr. Electron microprobe analysis using a scanning electron microscope, an energy dispersive X-ray detector, and a computer programme, to distinguish between characteristic and uncharacteristic radiations, allowed quantification of cellular ionic concentrations per kg tissue wet wt by comparison of the intensities of the emitted radiations from the cells and from the albumin layer. Granular, mitochondrial-rich, and basal cells, and the basal portions of goblet cells, showed a similar composition, being high in K (about 110 mM/kg wet wt) and low in Na (about 13 mM/kg wet wt). The apical portions of goblet cells were higher in Ca and S and lower in P and K, presumably reflecting the composition of the mucus within them. With Na-Ringer's as the mucosal medium, cells gained Na and lost K, when their serosal surfaces were exposed to ouabain, 10(-2) M. Replacement of mucosal Na by choline virtually prevented these ouabain-induced changes. Cellular ion contents were unchanged when Na in the serosal medium was replaced by choline. No differences in Na and K concentrations were detected between nuclei and cytoplasm. These results provide independent support for the hypothesis the the cellular Na transport pool in toad bladder epithelial cells derives exclusively from the mucosal medium and that no important recycling of Na occurs from the serosal medium to the cells.
已使用电子微探针分析技术测量了蟾蜍膀胱上皮细胞的电解质组成。将安装在小室中并用各种培养基冲洗过的半膀胱部分，在其黏膜表面铺上白蛋白溶液，然后立即在-180℃的液态丙烷中速冻。从冷冻材料上切下1 - 2微米厚的冷冻切片，并在-80℃和10^(-6)托下迅速冷冻干燥12小时。使用扫描电子显微镜、能量色散X射线探测器和计算机程序进行电子微探针分析，以区分特征辐射和非特征辐射，通过比较细胞和白蛋白层发出的辐射强度，可以对每千克组织湿重中的细胞离子浓度进行定量。颗粒细胞、富含线粒体的细胞和基底细胞，以及杯状细胞的基部，显示出相似的组成，钾含量高（约110 mM/kg湿重），钠含量低（约13 mM/kg湿重）。杯状细胞的顶端部分钙和硫含量较高，磷和钾含量较低，这可能反映了其中黏液的组成。当黏膜培养基为钠林格氏液时，当浆膜表面暴露于10^(-2) M的哇巴因时，细胞摄取钠并丢失钾。用胆碱替代黏膜中的钠实际上阻止了这些由哇巴因诱导的变化。当浆膜培养基中的钠被胆碱替代时，细胞离子含量不变。在细胞核和细胞质之间未检测到钠和钾浓度的差异。这些结果为以下假设提供了独立的支持：蟾蜍膀胱上皮细胞中的细胞钠转运池仅来自黏膜培养基，并且没有重要的钠从浆膜培养基循环到细胞中。
