Figure 7. Halothane primarily reduces the slow exponential component of S-channel closed times. Frequency histograms of open times (upper panels) and closed times (lower panels) in a cell-attached patch on a pleural neuron. The recording pipette contained artificial seawater and 10 mM tetraethylammonium. Vhwas +20 mV. Histograms show open- or closed-time durations either before (left) and during (right) perfusion of the cell with 650 micro Meter (0.017 atm) halothane. The smooth curve drawn through each histogram represents the maximum likelihood exponential fit to the data. The open and closed times were best fit by two exponential components with the indicated time constants.