In this cell ATPγS facilitated only spontaneous EPSC frequency with no effect on spontaneous IPSCs. A, ATPγS was applied during the period indicated by the horizontal bar. B, overlaid traces (five sweeps) during control (i), during the application of 100 μm ATPγS (ii) and after washout (iii) in the periods indicated by the filled bars in A. C, the time course of changes in sEPSC frequency are shown on the left, no changes were observed in sIPSC frequency (right).