BK channels in human glioma cells have enhanced calcium sensitivity.
作者： Christopher B. Ransom , Xiaojin Liu , Harald Sontheimer
DOI: 10.1002/GLIA.10064
关键词:
摘要: We have previously demonstrated the expression of large-conductance, calcium-activated potassium (BK) channels in human glioma cells. In present study, we characterized calcium sensitivity BK excised membrane patches. Channels inside-out patches were activated at -60 mV by 2.1 x 10(-6) M cytosolic Ca(2+), highly K(+)-selective, and had a slope conductance approximately iqual 210 pS. Ca(2+) these detail isolating currents outside-out with different free [Ca(2+)](i). The half-maximal voltage for channel activation, V(0.5), was +138 0 Ca(2+)/10 EGTA. V(0.5) shifted to +81 -14 [Ca(2+)](i) 1.5 10(-7) M, respectively. These results suggest that higher than described many other preparations. Data obtained from cloned (hbr5) expressed HEK cells support conclusion an unusually high calcium. addition, inhibitor tetrandrine suggests auxiliary beta-subunits Expression beta-subunit may relate channels.
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