Fig. 2 shows whole-cell current recordings of BK in HEK 293 cells transfected with BKα (see Methods), before and after treatment with 5 mM MβCD. An increase in whole-cell current (2–5 fold) by depletion of membrane cholesterol is evident (Fig. 2C). This result differs from findings obtained for BK channels in glioma cells [25] but is consistent with previously published bilayer data [6], as well as data obtained in IGR 39 cells [45]. The time course of current rise is gradual, with maximal current observed at about 10 minutes after the application of MβCD (Fig. 2D). This evidence concerns the gene KCNMA1 and central nervous system cancer.