Fig. 1.  Effects of posttraining administration of propofol on retention of an inhibitory avoidance response. Step-through latencies (mean ± SD) on a 48-h retention test. Immediate posttraining administration of propofol (300 mg/kg) enhanced memory retention. *P < 0.05; **P < 0.01 versus  vehicle; # P < 0.05; ## P < 0.01 versus  250 mg/kg propofol (n = 12, vehicle; n = 13, 250 and 300 mg/kg propofol; n = 9, 350 mg/kg propofol).