Figure 6. Maxi-K channel activity is regulated by NGF and muscarinic stimulation. A, Left, Traces of potassium outward currents recorded in whole-cell configuration from a neuron cultured without NGF before and after addition of 100 μm Cd2+. Pulse protocol: Cells were depolarized in 10 mV steps from a holding potential of −50 mV up to 20 mV for 500 ms per voltage step. Right, Same protocol as on the left, but with a cell cultured with 1 ng/ml NGF. B, Same type of experiments as in A, but with application 200 nm IbTX instead of Cd2+. C, D, Difference current densities (ΔIK, ± Cd2+ or ± IbTX) at a membrane potential of 0 mV calculated from recordings of neurons cultured without or with NGF as shown in A (p = 0.04) or (B) (p = 0.05). E, SCG neurons cultured in the absence of NGF were treated for 20 s with 250 nm BK or 10 μm Oxo-M, respectively, whereas potassium outward currents were recorded as shown in A. Bars represent difference current densities at a membrane potential of 0 mV under control conditions or after stimulation of cells with BK or Oxo-M (control vs Oxo-M p = 0.03, n.s., Not significant, p = 0.78). Numbers in parentheses indicate number of experiments.