Exogenously applied glutamate increases mIPSC amplitudes. A, Addition of 100 μm(black, closed circles; n = 1975 events) or 500 μm (black, open circles;n = 1477 events) glutamate (glu) increased mIPSC amplitude compared with control (gray, closed circles;n = 1990; gray, open circles;n = 1493, respectively). Cumulative probability histograms were constructed as described in the Figure4B legend. Inset, Average mIPSC waveforms from two representative cells in control solution (gray) and in the presence of either 100 μm (black, left) or 500 μm(black, right) glutamate. B, Preincubation with MPA, a GAD inhibitor, reduced the effect of 500 μm glutamate on mIPSC amplitude. The data for 500 μm glutamate from A(open circles) are included for comparison.Inset, Average mIPSC waveforms from a representative cell preincubated in MPA in control solution (gray) and in the presence of 500 μm glutamate (black). C, Three hundred micromolar THA blocked the effect of glutamate on mIPSCs. mIPSCs recorded during coapplication of 300 μm THA and 100 μm glutamate (black symbols;n = 1418 events) were not different compared with control (gray symbols; n = 1088 events). Inset, Average mIPSC waveforms from a representative cell in control solution (gray) and in the presence of 300 μm THA and 100 μm glutamate (black). D, Recorded at 34°C, addition of 100 μm glutamate (black symbols; n = 1177 events) increased mIPSC amplitude compared with control (gray symbols; n = 973 events).Inset, Average mIPSC waveforms from a representative cell in control solution (gray) and in the presence of 100 μm glutamate (black).norm, Normalized.