Pflügers Archiv

, Volume 398, Issue 3, pp 179–188

Noise analysis of inward and outward Na+ currents across the apical border of ouabain-treated frog skin

  • Willy Van Driessche
  • David Erlij

DOI: 10.1007/BF00657149

Cite this article as:
Van Driessche, W. & Erlij, D. Pflugers Arch. (1983) 398: 179. doi:10.1007/BF00657149


The passive Na+ transport across the apical membrane of frog skin (Rana catesbeiana) was studied under the following circumstances: (1) control conditions (sulfate Ringer's, K+ depolarised serosal membranes); (2) after blocking the active transport step with ouabain; (3) with an outward oriented Na+ current. The amiloride-induced Na+ current fluctuations were analysed to calculated the density of amiloride blockable channels and the current through one single channel. Despite the large reduction of the macroscopic current by oubain, the single channel current remained unchanged, while the number of amiloride blockable Na+ channels was reduced by a factor of eight. It is concluded from these observations that the earlier described reduction of the permeability of the apical membrane is caused by a decrease of the number of electrically conductive Na+ channels. The outward oriented single channel currents were less than 50% of the currents in the opposite direction. After ouabain, the number of Na+ channels was independent from the current direction.

Key words

Frog skinFluctuation analysisOuabainAmilorideApical membrane permeabilityNa+ channelOutward current

Copyright information

© Springer-Verlag 1983

Authors and Affiliations

  • Willy Van Driessche
    • 1
  • David Erlij
    • 2
  1. 1.Labo voor FysiologieLeuvenBelgium
  2. 2.Department of PhysiologySUNY Down State Medical CenterBrooklynUSA