Figure 5. Closed time distributions for α3 AChRs expressed in oocytes.

Examples of closed time distributions were fitted with exponential functions as described in Methods. For these patches, four components could adequately describe the data. The time constants determined from the fits are given for each patch. These values were used to set the critical times for burst definitions. For α3β2 and α3α5β2 AChRs, the fastest time constant was defined as the intraburst closed time, while the three longer time constants were set as between burst closed times. For α3β4 and α3α5β4 AChRs, the two shortest time constants were set as intraburst closed times, while the two longest time constants were set as between burst closed times. Channels were activated by 1 μM ACh for α3β2 and α3α5β2, while 5 μM ACh was used for α3β4 and α3α5β4 AChRs. The holding potential was -80 mV.