Figure 3.
BK conductance promotes bursting in GH4C1 cells. A, Left, Time course of the membrane potential of a GH4C1 cell in control conditions. Right, Histogram of event duration; the vertical line separates events between spikes and bursts. B, Voltage time course and event distribution for the same cell after iberiotoxin (IBTX, 100 nm) application. All events have shorter duration and higher amplitude (spikes). C, After adding an artificial fast-activating BK conductance (gBK = 0.5 nS) via dynamic clamp, the cell exhibits bursting with amplitude and duration similar to control conditions. D, Median and interquartile range of burstiness factor for spikers (BF ≤ 0.3, triangles) and bursters (BF > 0.3, circles) in control conditions (n = 5 and 8, respectively), BK block (with either 1 μm paxilline or 100 nm IBTX), and after adding an artificial BK conductance in the presence of a BK blocker (gBK = 0.5 nS; n = 4 and 4). Addition of gBK (0.5 nS) restored burstiness to control or above control level in seven of eight cells [in the remaining cell, a larger BK conductance (gBK = 1nS) could also bring burstiness back to control level].