Fig. 4. Effects of spiroxatrine on passive avoidance performance in rats injected with intravenous anesthetics. Training day ( A , ○); testing day ( B , •). The vehicle (Veh) or spiroxatrine (5 μg, Spi) was injected intracerebroventricularly 30 min before training, with saline (Sal), propofol (60 mg/kg, Pro), midazolam (5 mg/kg, Mid), or pentobarbital (15 mg/kg, Pen) injected intraperitoneally immediately after training. The step-through retention latencies were measured 24 h later. ** P < 0.01 as compared with each corresponding value in the vehicle-with-saline group (midazolam vs. saline: U = 0, P = 0.0006; propofol vs. saline: U = 5.5, P = 0.0043). ++ P < 0.01 as compared with each corresponding spiroxatrine group. (Midazolam: U = 0, P = 0.0007; propofol: U = 5.5, P = 0.0043.)