a, Example traces showing evoked EPSCs when cells were held at –80 mV. NMDAR EPSCs were isolated by application of picrotoxin (100 μM) and NBQX (10 μM) in Mg2+-free ACSF, and confirmed by AP5 (100 μM) blockade. b, Amplitudes of NMDAR EPSCs under different voltages (EPSCs are recorded under 0 Mg2+, picrotoxin and NBQX). Note that isolated NMDAR EPSCs are completely blocked by AP5. c–f, Ketamine (c), AP5 (d), NBQX (e) and mibefradil (f) do not affect RMPs of LHb neurons. n = 10 neurons, 5 rats (c); n = 17 neurons, 6 rats (d); n = 11 neurons, 6 rats (e); n = 10 neurons, 3 rats (f). g, ZD7288 causes a small but significant hyperpolarization of LHb neurons. n = 9 neurons, 4 rats. h, Example mEPSC traces before (black) and after (red) perfusion of ketamine (100 μM, see Methods) measured in a whole-cell configuration (cells were held at –60 mV) from LHb neurons. i, j, Cumulative distribution of mEPSC amplitude (i) or mEPSC inter-events interval and average frequency (j) of neurons before (black) or after (red) ketamine treatment. Each line represents values before or after treatment with ketamine from the same LHb neuron. n = 9 neurons, 2 rats. Data are mean ± s.e.m.; *P < 0.05, n.s., not significant. Two-tailed paired t-test.