Fig. 2.
D54-MG cells express functional large-conductance calcium-activated potassium channel (BK) and intermediate-conductance calcium-activated potassium channel (IK) channels. A: Western blots of glioma cell lines probed for BK channels, IK channels and GAPDH as a loading control. B and C: whole cell patch-clamp recordings of D54-MG cells with ∼150 nM internal free Ca2+ using a step protocol from a −40-mV holding potential stepping from −120 to +120 mV at 20-mV intervals. B: representative trace of paxilline-sensitive current and average data illustrating BK currents, recorded in the presence of 200 μM DIDS to block chloride currents (n = 7); scale bars represent 100 ms and 5,000 pA. C: representative trace of clotrimazole-sensitive currents and average data illustrating IK currents, recorded in the presence of 2 μM paxilline and 130 mM gluconate to block BK and chloride currents, respectively (n = 4); scale bars represent 50 ms and 150 pA.