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Polarized expression of cAMP-activated chloride channels in isolated epithelial cells.

Publication ,  Journal Article
Torres, RJ; Altenberg, GA; Cohn, JA; Reuss, L
Published in: Am J Physiol
November 1996

We have described a preparation of Necturus maculosus gallbladder (NGB) epithelium yielding isolated cells that retain structural and functional polarity ("figure-eight" cells). These cells have a normal membrane voltage and remain polarized for several hours after isolation. Apical and basolateral membrane domains are differentially labeled with hydrophobic fluorescent dyes; freeze-fracture electron microscopy reveals two distinct membrane domains separated by tight junctions; ZO-1, Na+/H+ exchanger (NHE3), and Na(+)-K(+)-ATPase are present in the junctional, apical, and basolateral region, respectively; and cell-attached patch-clamp experiments reveal different K+ currents in the two membrane domains [R. J. Torres, G. A. Altenberg, J. A. Copello, G. Zampighi, and L. Reuss, Am. J. Physiol. 270 (Cell Physiol. 39): C1864-C1874, 1996]. Here, we show that NGB epithelial cells express a protein cross-reactive with an antibody against human cystic fibrosis transmembrane conductance regulator (CFTR). In figure-eight cells, immunoreactivity was restricted to the apical membrane domain. Using intracellular microelectrodes and a novel method of regional superfusion, we found that control cells have high K+ conductances in both membranes and a small basolateral Cl- conductance, similar to findings in the epithelium. Activation of adenylate cyclase with forskolin elicited a large apical membrane Cl- conductance and membrane depolarization. Whole cell patch-clamp studies yielded a forskolin-activated linear Cl- current, with high Cl-/aspartate selectivity. In conclusion, 1) figure-eight cells maintain the conductive membrane properties present in the epithelium, including polarized expression of adenosine 3',5'-cyclic monophosphate (cAMP)-activated Cl- channels, and 2) the cAMP-activated Cl- conductance is underlied by a CFTR homologue.

Duke Scholars

Published In

Am J Physiol

DOI

ISSN

0002-9513

Publication Date

November 1996

Volume

271

Issue

5 Pt 1

Start / End Page

C1574 / C1582

Location

United States

Related Subject Headings

  • Rabbits
  • Patch-Clamp Techniques
  • Necturus
  • Microelectrodes
  • Membrane Potentials
  • Kinetics
  • Humans
  • Gallbladder
  • Epithelium
  • Epithelial Cells
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Torres, R. J., Altenberg, G. A., Cohn, J. A., & Reuss, L. (1996). Polarized expression of cAMP-activated chloride channels in isolated epithelial cells. Am J Physiol, 271(5 Pt 1), C1574–C1582. https://doi.org/10.1152/ajpcell.1996.271.5.C1574
Torres, R. J., G. A. Altenberg, J. A. Cohn, and L. Reuss. “Polarized expression of cAMP-activated chloride channels in isolated epithelial cells.Am J Physiol 271, no. 5 Pt 1 (November 1996): C1574–82. https://doi.org/10.1152/ajpcell.1996.271.5.C1574.
Torres RJ, Altenberg GA, Cohn JA, Reuss L. Polarized expression of cAMP-activated chloride channels in isolated epithelial cells. Am J Physiol. 1996 Nov;271(5 Pt 1):C1574–82.
Torres, R. J., et al. “Polarized expression of cAMP-activated chloride channels in isolated epithelial cells.Am J Physiol, vol. 271, no. 5 Pt 1, Nov. 1996, pp. C1574–82. Pubmed, doi:10.1152/ajpcell.1996.271.5.C1574.
Torres RJ, Altenberg GA, Cohn JA, Reuss L. Polarized expression of cAMP-activated chloride channels in isolated epithelial cells. Am J Physiol. 1996 Nov;271(5 Pt 1):C1574–C1582.

Published In

Am J Physiol

DOI

ISSN

0002-9513

Publication Date

November 1996

Volume

271

Issue

5 Pt 1

Start / End Page

C1574 / C1582

Location

United States

Related Subject Headings

  • Rabbits
  • Patch-Clamp Techniques
  • Necturus
  • Microelectrodes
  • Membrane Potentials
  • Kinetics
  • Humans
  • Gallbladder
  • Epithelium
  • Epithelial Cells