Figure 7. Ketamine (50 micro Meter) added to the bath solution reversibly inhibited channels present in cell-attached patches. Single-channel currents were recorded from the same cell, in the absence and presence of ketamine. The durations of closed times are plotted as the distribution of log time versus the bin frequency. In the absence of ketamine, the distribution was fitted with the sum of three exponential functions, with time constants and relative areas of tau¹= 0.32 ms, a¹= 0.56, tau²= 5.3, a²= 0.13, tau³= 80.7 ms, and a³= 0.32, whereas tau¹= 0.23 ms, a¹= 0.53, tau²= 5.1 ms, a²= 0.14, tau³, = 838.93 ms, a³= 0.33 for currents recorded in the presence of ketamine. The mean closed times for the illustrated tracings were tau^ccontrol = 38.9 +/- 1.21 ms (n = 3662 events) and tau^cketamine = 412 +/- 36.86 (n = 390), whereas the mean channel-open times were tau^ocontrol = 2.82 +/- 0.48 ms (n = 3,539) and tau^oketamine = 1.61 +/- 0.07 ms (n = 482).