Whole-cell voltage clamp measurements of human glioblastoma cells. Holding potential = -30 mV. A. Current-voltage plots obtained during voltage ramps from -100 to 100 mV (300 ms duration). Plots were obtained before (control) and after added paxilline (2 μM). B. Whole-cell currents obtained at -90 and 90 mV plotted versus time before and after added paxilline (2 μM). Reversed symbols are from I-V plots shown in A. C. Whole-cell currents recorded during voltage steps from -30 to 90 mV before and after added paxilline (2 μM). D. Summary results (as in C) of the effects of paxilline on outward, whole-cell currents recorded at voltage steps to 90 mV.