Pflügers Archiv

, Volume 394, Issue 4, pp 287–293

Poorly selective cation channels in the skin of the larval frog (Stage≤XIX)

  • Stanley D. Hillyard
  • Wolfgang Zeiske
  • Willy Van Driessche
Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands

DOI: 10.1007/BF00583692

Cite this article as:
Hillyard, S.D., Zeiske, W. & Van Driessche, W. Pflugers Arch. (1982) 394: 287. doi:10.1007/BF00583692

Abstract

The abdominal skin of bullfrog larvae (Rana catesbeiana) was placed in an Ussing-type chamber, and its transepithelial electrical parameters were recorded with mucosal solutions of different ionic composition. With “K+-like” cations (K+, NH4+, Rb+, Cs) the power spectra of the fluctuations in short-circuit current displayed a Lorentzian component (fc=30–40 Hz). The relaxation noise could be suppressed by addition of the K+-channel blockers Ba2+ and TEA to the mucosal solution. Also, in presence of the ionophore antibiotic nystatin the Lorentzian noise was abolished. The Na+-channel probes amiloride and benzimidazolyl-2-guanidine (BIG) both enhanced the relaxation noise obtained with the K+-like cations but, with Na+, and Li+, also caused the rise of a relaxation component above the background noise. In presence of amiloride or BIG, the addition of Ba2+, TEA and nystatin still abolished the Lorentzian noise. It can be concluded that the relaxation-noise source is located in the apical cell membranes of the tadpole skin. These spontaneously fluctuating cation channels do not seem to strictly discriminate between K+-like ions (K+, NH4+, Rb+, Cs+) and Na+-like ions (Na+, Li+). On the other hand, well-known specific probes for K+ channels (Ba2+, TEA) and for Na+ channels (amiloride, BIG) interact with this apical cation channel. It is possible that the poorly selective channel plays a role in the ontogenesis of the specific Na+ transport in the maturing frog skin.

Key words

Noise analysis Tadpole skin Apical membrane Cation channel Barium TEA (Tetraethyl ammonium) Amiloride 

Copyright information

© Springer-Verlag 1982

Authors and Affiliations

  • Stanley D. Hillyard
    • 1
  • Wolfgang Zeiske
    • 1
  • Willy Van Driessche
    • 1
  1. 1.Laboratorium voor FysiologieK.U.L.LeuvenBelgium
  2. 2.Desert Biology Research CenterUniversity of NevadaLas VegasUSA

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