Stimulation of M-type K+ channels with flupirtine reduced the intrinsic excitability of IL pyramidal neurons. A, Traces showing the number of spikes evoked by a current pulse during baseline, perfusion with the M-type K+ channel agonist (flupirtine, 30 μm) and washout. B, C, Time course and bar graph showing that flupirtine application decreased the number of evoked spikes in IL pyramidal neurons (n = 6). D, Flupirtine also increased the interspike intervals, consistent with reduced bursting in IL. (**p < 0.001).