Fig. 5. Suppression of outward Cl−gradient eliminates excitatory action of propofol. ( A ) Traces from a dissociated ventrolateral preoptic nucleus neuron show a much smaller effect of propofol (10 μm) on the frequency of spontaneous excitatory postsynaptic currents (sEPSCs) in the presence of 10 μm bumetanide, a blocker of Na+–K+–Cl−cotransporter. ( B ) Time course of changes in frequency. ( C ) Means ± SEM from four cells. * P < 0.05 by paired t test for propofol versus prepropofol data.