Figure 4: Guanosine 5’-[βthiol]diphophate (GDPβS) applied through the recording pipette had no effect on paired pulse facilitation of excitatory postsynaptic currents (EPSCs). A: Paired EPSCs evoked at 100 ms intervals resulted in an increase of the second EPSC amplitude as compared to the first one in control condition. B: Paired EPSCs evoked at 100 ms intervals after 10 minutes of recording in the presence of GDPβS. C: Summary histogram showing the % increase of EPSC2 amplitude as compared to EPSC1 in the control and in the presence of GDPβS. Error bar represent the sem.