Recordings were performed in ACSF perfused at 5 mL/min at 25 °C. Patch glass micropipettes (Warner Instruments) had a resistance 2.5–5 MΩ and the intra-pipette solution contained (in mM) 144 potassium gluconate, 10 HEPES, 3 MgCl2, 2 Na2-ATP, 0.3 GTP and 0.2 EGTA, adjusted to pH 7.2 with KOH.