Spontaneously opening GABAA receptors play a significant role in neuronal signal filtering and integration

a Example traces of whole-cell continuous recordings from DGCs. Top: Full experimental trace; application of SR (25？μM) blocks GABA-dependent phasic conductance, whereas subsequent application of SR？+？PTX (50？μM) blocks tonic conductance controlled by s-GABAARs. Horizontal dashed lines mark time intervals over which Itonic was averaged for SR and SR？+？PTX. Medium: Expanded section of the recording demonstrates the effect of s-GABAARs blocked by PTX. Shaded area shows the amount of tonic current controlled by s-GABAARs. Bottom: Expanded 0.5-s recording interval before application of SR. Shaded area shows the amount of inhibitory current transferred with GABA-induced phasic events. b Statistical summary on effects of s-GABAARs and GABA-dependent effects. Top: SR and SR？+？PTX decrease RMS noise; bars represent change (ΔRMS) from RMS in control (for SR) and from RMS under SR (for SR？+？PTX), asterisks indicate significance of difference from zero; n？=？6, Student’s paired t test. Medium: Shifts of Ihold induced by the application of SR and SR？+？PTX; ΔIhold for SR and SR？+？PTX was calculated similarly to ΔRMS. Asterisks indicate significance of difference from zero; n？=？6, Student’s paired t test. Bottom: Input into inhibitory charge transfer delivered by GABA-dependent GABAARs (phasic events suppressed by SR) and s-GABAARs (tonic response suppressed by SR？+？PTX). n？=？6, Student’s paired t test. Colour codes apply for all three bar charts, **P？<？0.01, ***P？<？0.00