Abstract
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 language | English |
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Pages (from-to) | 63-72 |
Number of pages | 10 |
Journal | BBA - Biomembranes |
Volume | 1149 |
Issue number | 1 |
DOIs | |
Publication status | Published - 18 Jun 1993 |
Keywords
- (Chick osteoclast)
- Calcium ion concentration, intracellular
- Calcium ion dependence
- Depolarization
- Patch clamp
- Potassium ion channel