ISSN:
1432-1424
Keywords:
Ca2+-activated K+ channel
;
Ca2+ oscillation
;
inward rectification
;
charybdotoxin
;
apamin
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary Calcium-activated potassium channels were the channels most frequently observed in primary cultured normal mammary cell and in the established mammary tumor cell, MMT060562. In both cells, single-channel and whole-cell clamp recordings sometimes showed slow oscillations of the Ca2+-gated K+ current. The characteristics of the Ca2+-activated K+ channels in normal and cancerous mammary cells were quite similar. The slope conductances changed from 8 to 70 pS depending on the mode of recording and the ionic composition in the patch electrode. The open probability of this channel increased between 0.1 to 1 μm of the intracellular Ca2+, but it was independent of the membrane potential. Charybdotoxin reduced the activity of the Ca2+-activated K+ channel and the oscillation of the membrane current, but apamin had no apparent effect. The application of tetraethylammonium (TEA) from outside and BaCl2 from inside of the cell diminished the activity of the channel. The properties of this channel were different from those of both the large conductance (BK or MAXI K) and small conductance (SK) type Ca2+-activated K+ channels.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01871412
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