Both open- and closed-time distributions are modified by cholesterol and other monohydroxysterols that decrease BK channel activity. Open- (left) and closed- (right panels) time distributions of cbv1 channels incorporated into control (first row of panels), cholesterol- (second row), coprostanol- (third row), or cholestanol-containing (last row) bilayers. Po values are 0.74, 0.34, 0.54, and 0.63 for control, cholesterol-, coprostanol-, and cholestanol-containing bilayers, respectively. Dwell-time distributions were obtained from 30 min of continuous recording of single-channel activity in each bilayer type. Data were fitted to exponential functions, and the minimum number of exponentials used to properly fit the data was determined as described in Materials and methods. Dotted lines indicate the individual component of the fit, with solid lines providing the composite exponential fit. Each panel contains the averaged duration of each time constant (in milliseconds). The relative contribution of each exponential component (defined by τ) to the total time spent in open or closed states is given in parentheses as a percentage of the total fitted area. The summation of products of each τ multiplied by its fractional contribution to the total fit was used to obtain the mean open and mean closed times shown in Fig. 7.