The presence of calcium-activated potassium channels in chondrocytes of growing cartilage was tested. Results obtained with fura-2 on cultured resting chondrocytes indicate that the cells respond to an elevation of extracellular calcium concentration ( [Ca2+]o ) from 0.1 to 2 mM increasing the intracellular concentration of the ion ( [Ca2+]i ) from 117 to 187 nM. This increment may be blocked by 3μM La3+. Patch clamp experiments in cell-attached configuration showed that, when [Ca2+]i rises, the open probability (Po) of the K+ channels increases. Increments in both Po and unitary currents of the K+ channels can be obtained after applying 2.5μM A23187 with 2mM [Ca2+]o. Hence, the results demonstrate that, in chondrocytes, a class of Ca2+-activated K+ channels is present and their activity is related to an increase of [Ca2+]i.
|Original language||English (US)|
|Number of pages||6|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Feb 14 1992|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology