not-yet-known not-yet-known not-yet-known unknown Excitatory postsynaptic currents (EPSCs) recordings Acute hippocampal slices were individually fixed with a grid in a recording chamber and continuously superfused by a gravitational superfusion system at 2-3 mL/minute with aCSF at RT. The aCSF was supplemented with picrotoxin (50 μM), to block the fast component of GABAergic transmission. Electrode positioning and cell selection were performed under visual guidance using a Carl Zeiss Axioskop 2FS upright microscope (Jena, Germany) equipped with a differential interference contrast-infrared (DIC-IR) CCD video camera (VX44, Till Photonics, Gräfelfing, Germany). EPSCs were recorded from the CA1 area upon stimulation (S48 Square Pulse Stimulator, Grass Instruments) of the Schaffer Collateral afferents with 0.1 millisecond rectangular pulses (0.1-0.5 mA) delivered once every 15 seconds through a concentric bipolar electrode placed in the stratum radiatum . Patch pipettes were filled with an intracellular solution (290-300 mOsm; pH 7.2, adjusted with 1M KOH) containing (mM): K-gluconate 145, HEPES 20, KOH 10, NaCl 8, EGTA 0.2, MgATP 2, NaGTP 0.3, (4-9 MΩ). Recordings were in whole-cell voltage-clamp mode (Vh = -70 mv) with an Axopatch 200B amplifier (Axon Instruments, CA, USA). The junction potential was not compensated for and offset potentials were nulled before giga-seal formation. Small voltage steps (5 mV, 50 milliseconds) were delivered throughout the experiment to monitor the access resistance; the holding current was also constantly monitored and when any of these parameters varied by more than 20% the experiment was rejected. The current signal was low-pass filtered using a 3- and 10-kHz three-pole Bessel filter, digitized at 10 kHz using a Digidata 1322A board, recorded by the pClamp software and analysed with Clampfit 10. EPSCs recordings were started not before the first 5–10 minutes after going to whole cell mode to allow diffusion of the intracellular solution. After 10 minutes of stable EPSCs recordings, the test drugs were added to the aCSF. Averages of 4 consecutive individual recordings (1 minute) were used for analysis.