On-cell patch clamp measurements of human glioblastoma cells. A. Relative frequency of channel opening (probability density function) plotted versus channel current. Peaks at specified currents are indicated by Gaussian fit. The analysis was of the displayed readout of patch current obtained from 6.3 s of on cell recording at pipette potential = -100 mV; (c)-closed state; (o)-open state. (inset) Membrane/patch current plotted as a function of patch pipette potential from -100 to 100 mV (300 ms duration). B. On-cell outward patch currents obtained from voltage ramps (-100 to 100 mV; 300 ms duration) before, during and after menthol treatment of the cell. C. Kinetic analysis of on-cell channel recording (-100 mV pipette potential) before and after menthol added to the bath (100 μM). Numbered traces correspond to numbered segments of the analysis.