Pentobarbital sodium alters spontaneous activity of NTS, VRC, and cortical neurons. A: mean normalized firing rate is shown for cortical neurons in slices from summer-active (SA) squirrels (n = 6; n = 77 neurons; open circles) and IBA squirrels (n = 6; n = 79 neurons, solid circles) in response to 300 μM pentobarbital sodium (applied at vertical line). At 120 min, neuronal activity from both SA and IBA squirrels was decreased significantly compared with time control (P < 0.001). IBA time controls are shown (n = 4; n = 22 neurons; gray circles). B: mean normalized firing rate is shown for VRC neurons in slices from SA squirrels (n = 6; n = 21 neurons; open squares) and IBA squirrels (n = 7; n = 54 neurons; solid squares). At 120 min, SA neuron activity was decreased compared with time controls (P < 0.001), while IBA neuron activity was not different from time controls (P > 0.05) IBA time controls are shown (n = 4; n = 40 neurons; gray squares). C: mean normalized firing rate is shown for NTS neurons in slices from SA squirrels (n = 6; n = 50 neurons, open triangles) and IBA squirrels (n = 7; n = 37 neurons; solid triangles). At 120 min, SA neuron activity was decreased compared with time controls (P < 0.01), while IBA neuron activity did not differ from time controls (P = 0.091). IBA time controls are shown (n = 4; n = 12 neurons; gray triangles). Error bars indicate means ± SE. †P < 0.05 compared with time controls.