Fig. 3. Effects of various concentrations of propofol on long-term potentiation. Propofol was dissolved in dimethyl sulfoxide (DMSO) and continuously administered for the duration shown by the  solid bars . One hundred–hertz θ-burst stimulation (TBS) was delivered at time 0 (  arrow ). TBS induced long-term potentiation when 0.1% DMSO alone was administered (  A ) or when 3 μm propofol was administered (  B ). Administration of 10 μm propofol significantly depressed long-term potentiation production (  C ), whereas 30 μm propofol completely blocked long-term potentiation (  D ).  Traces to the right of the graphs depict representative excitatory postsynaptic potentials (EPSPs) obtained before (  dashed traces ) and 60 min after TBS (  solid traces ). EPSPs were obtained from slices treated with DMSO alone (  upper traces ), 3 μm propofol (  second set of traces ), 10 μm propofol (  third traces ), and 30 μm propofol (  bottom traces ).  Scale bar : 2 mV, 5 ms .