Whole-cell patch-clamp recordings were performed using Multiclamp 700A patch-clamp amplifier (Molecular Devices, Palo Alto, CA) as previously described21. Briefly, the recording chamber was constantly perfused with a bath solution consisting of 128 mM NaCl, 30 mM glucose, 25 mM HEPES, 5 mM KCl, 2 mM CaCl2, and 1 mM MgCl2 (pH7.3; 315–325 mOsm per litre). Patch pipettes were pulled from borosilicate glass (3–5 MΩ) and filled with an internal solution consisting of 135 mM KGluconate, 10 mM Trisphosphocreatine, 10 mM HEPES, 5mM EGTA, 4 mM MgATP, and 0.5 mM Na2GTP (pH 7.3). The series resistance was typically 10–30 MΩ. For SSC recording, the membrane potential was typically held at −70 mV. Drugs were applied through a gravitydriven drug delivery system (VC-6, Warner Hamden, CT). Data were acquired using pClamp 9 software (Molecular Devices, Palo Alto, CA), sampled at 10 kHz and filtered at 1 kHz. Spontaneous synaptic events were analysed using MiniAnalysis software (Synaptosoft, Decatur, GA). All experiments were conducted at room temperature.
