Figure 4

TWIK-1 deficiency in dentate granule cells causes enhanced amplitude of evoked EPSPs in response to perforant path stimulation. (A) ( a ) Schematic diagram for synaptically evoked responsiveness of dentate granule cells. PP: perforant path, Stim: stimulation, Rec: recording. ( b ) Representative traces of evoked EPSPs in naïve, Sc shRNA or TWIK-1 shRNA expressing dentate granule cells. Synaptic responses evoked by 150 μA stimulation of perforant path are shown. ( c ) Input-output properties of dentate granule cells. Plotted values are of evoked EPSP amplitudes in naïve (n = 13cells, N = 3 mice), Sc shRNA (n = 14 cells, N = 3 mice) or TWIK-1 shRNA (n = 12 cells, N = 3 mice) expressing granule cells. The RMP was maintained at -80mV by steady current injection. For each stimulation intensity, ten perforant path stimuli were applied and the evoked EPSP responses were averaged. The solid line is a logistic fit of the data plots. ACSF contained 10 μM bicuculline and 10μM CGP 55845; pipette solution contained 5 mM QX-314. (B) Representative traces for paired-pulse ratio measurements (left panel). Paired-pulse ratios in perforant path to granule cell synaptic transmission as a function of interstimulus interval (ISI) in naïve (n = 16 cells, N = 3 mice), Sc shRNA (n = 16 cells, N = 3 mice) or TWIK-1 shRNA (n = 16 cells, N = 3 mice) expressing cells (right panel). ACSF contained 10 μM bicuculline and 10 μM CGP 55845; pipette solution contained 5 mM QX-314. All data are represented as mean ± S.E.M; *P < 0.05, Student's unpaired t-test.