On day 1, there was a significant effect of genotype on latency to enter the dark compartment (P<0.05). Wild-type mice, saline control, n=20; wild-type mice, thioperamide-treated (5 mg/kg intraperitoneally), n=21; Apoe−/− mice, saline control, n=15; Apoe−/− mice, hioperamide-treated (5 mg/kg intraperitoneally), n=16. *P<0.01 compared with day 1.