Fig. 5. Summary of the effects of propofol and pentobarbital on the induction of  N -methyl-d-aspartate receptor–dependent long-term potentiation and  N -methyl-d-aspartate receptor–independent long-term potentiation. One hundred–hertz or 200-Hz θ-burst stimulation was delivered in control slices (  open bars ), in the presence of 30 μm propofol (  filled bars ) or 30 μm pentobarbital (  hatched bars ) . *P < 0.05 by Student  t test .