Maxi K+ channels on human vas deferens epithelial cells

Y. Sohma, A. Harris, C. J.C. Wardle, M. A. Gray, B. E. Argent

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

The vas deferens forms part of the male reproductive tract and extends from the cauda epididymis to the prostate. Using the patch clamp technique, we have identified a Ca2+-activated, voltage-dependent, maxi K+ channel on the apical membrane of epithelial cells cultured from human fetal vas deferens. The channel had a conductance of ∼250 pS in symmetrical 140 m m K+ solutions, and was highly selective for K+ over Na+. Channel activity was increased by depolarization and by an elevation of bath (cytoplasmic) Ca2+ concentration, and reduced by cytoplasmic Ba2+ (5 m m) but not by cytoplasmic TEA (10 m m). Channel activity was also dependent on the cation bathing the cytoplasmic face of the membrane, being higher in a Na+-rich compared to a K+-rich solution. We estimated that up to 600 maxi K+ channels were present on the apical membrane of a vas cell, and that their density was 1-2 per μ2 of membrane. Activity of the channel was low on intact cells, suggesting that it does not contribute to a resting K+ conductance. However, fluid in the lumen of the human vas deferens has a high K+ concentration and we speculate that the maxi K+ channel could play a role in transepithelial K+ secretion.

Original languageEnglish
Pages (from-to)69-82
Number of pages14
JournalThe Journal of Membrane Biology
Volume141
Issue number1
DOIs
Publication statusPublished - 1994 Jul

Keywords

  • Apical membrane
  • Epithelium
  • Human vas deferens
  • K secretion
  • Patch clamp

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

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