A Ca2+-dependent K+-channel in freshly isolated and cultured chick osteoclasts

Adam F. Weidema, Jan H. Ravesloot, György Panyi, Peter J. Nijweide, Dirk L. Ypey

Research output: Contribution to journalArticle

12 Citations (Scopus)


Calcium-activated potassium channels were found in embryonic chick osteoclasts using the patch-clamp technique. The activity of the channel was increased by both membrane depolarisation and an increase in intracellular Ca2+ concentration in the range 10-5 to 10-3 M. In the cell-attached-patch configuration the channel was only active at extreme depolarising potentials. Ca2+ addition to the cytoplasm via ionomycin increased channel activity at the resting membrane potential of the osteoclast. The channel had a single-channel conductance of 150 pS in the inside-out patch under symmetrical K+ conditions (150 mM) and was selective for potassium ions. During sustained application of increased [Ca2+] at the cytoplasmic side of inside-out patches, channel activity sometimes decreased again after the initial increase (desensitization). The results established the properties of the single channels underlying an outward rectifying K+ conductance in chick osteoclasts described previously by us.

Original languageEnglish
Pages (from-to)63-72
Number of pages10
JournalBBA - Biomembranes
Issue number1
Publication statusPublished - Jun 18 1993


  • (Chick osteoclast)
  • Calcium ion concentration, intracellular
  • Calcium ion dependence
  • Depolarization
  • Patch clamp
  • Potassium ion channel

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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