The Journal of Membrane Biology

, Volume 124, Issue 1, pp 1–12

Basolateral membrane potassium conductance of A6 cells

  • Marie-Christine Broillet
  • Jean-Daniel Horisberger

DOI: 10.1007/BF01871359

Cite this article as:
Broillet, MC. & Horisberger, JD. J. Membrain Biol. (1991) 124: 1. doi:10.1007/BF01871359


To study the properties of the basolateral membrane conductance of an amphibian epithelial cell line, we have adapted the technique of apical membrane selective permeabilization (Wills, N.K., Lewis, S.A., Eaton, D.C., 1979b, J. Membrane Biol.45:81–108). Monolayers of A6 cells cultured on permeable supports were exposed to amphotericin B. The apical membrane was effectively permeabilized, while the high electrical resistance of the tight junctions and the ionic selectivity of the basolateral membrane were preserved. Thus the transepithelial current-voltage relation reflected mostly the properties of the basolateral membrane. Under “basal” conditions, the basolateral membrane conductance was inward rectifying, highly sensitive to barium but not to quinidine. After the induction of cell swelling either by adding chloride to the apical solution or by lowering the osmolarity of the basolateral solution, a large out-ward-rectifying K+ conductance was observed, and addition of barium or quinidine to the basolateral side inhibited, respectively, 82.4±1.9% and 90.9±1.0% of the transepithelial current at 0 mV. Barium block was voltage dependent; the half-inhibition constant (Ki) varied from 1499±97 μm at 0 mV to 5.7±0.5 μm at −120 mV.

Cell swelling induces a large quinidine-sensitive K+ conductance, changing the inward-rectifying basolateral membrane conductance observed under “basal” conditions into a conductance with outward-rectifying properties.

Key Words

A6 cells amphotericin B basolateral membrane K+ conductance cell volume barium quinidine 

Copyright information

© Springer-Verlag New York Inc. 1991

Authors and Affiliations

  • Marie-Christine Broillet
    • 1
  • Jean-Daniel Horisberger
    • 1
  1. 1.Institut de PharmacologieUniversité de LausanneLausanneSwitzerland

Personalised recommendations