Figure 4. Cs⁺ suppresses I_IR

I_IR decreases input resistance and increases the current required to evoke oscillatory potentials. A: Voltage-clamp experiment in the control condition. Voltage steps were from -111 mV to -1 mV, in 10 mV steps, for 200 msec. B: The same voltage-clamp experiment as in panel A with Cs⁺ (5 mM) in the extracellular solution. C: The I-V relationship in the sustained state for panels A and B. Filled circles, control; Open squares, Cs⁺. D: Current-clamp experiment in the control condition. Injected currents were from -40 pA to 80 pA, in 20 pA steps, for 200 msec. Input resistance of this cell was calculated as 465 MΩ. Current injection of +80 pA evoked oscillatory potentials (arrow). E: The same current clamp experiment as in panel D with Cs⁺ (5 mM) in the extracellular solution. Input resistance of this cell was increased to 3927 MΩ. Oscillatory potentials are indicated by an arrow. F: Line plots for all nine cells examined.