Summary
The intracellular Na and K concentrations in the different layers of the frog skin were measured using the electron microprobe. The experiments were carried out under control conditions and after inhibition of the transcellular Na transport by ouabain, amiloride and reduction of the Na concentration in the epithelial bathing solution to zero. After measuring the short-circuit current in an Ussing type chamber the skin was shockfrozen at-140°C, cryosectioned (2–3 μm) at-70°C and freezedried. For quantitation sections from albumin solution with known electrolyte concentrations were prepared in the same manner as the skin. After ouabain the Na concentrations of all epithelial cells increased, whereas the K concentration decreased to the same extent. The action of amiloride and the incubation of the epithelial side with Na-free Ringer solution caused a decrease of intracellular Na concentration only in the outermost functional cell layer of the frog skin. Therefore it is concluded that this cell layer is responsible for transcellular Na transport. In most experiments the cornified layer showed the same electrolyte concentrations as the epithelial bathing solution, which were not altered by amiloride or ouabain.
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Dörge, A., Gehring, K., Nagel, W. et al. Localization of sodium in forg skin by electron microprobe analysis. Naunyn-Schmiedeberg's Arch. Pharmacol. 281, 271–280 (1974). https://doi.org/10.1007/BF00500596
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DOI: https://doi.org/10.1007/BF00500596