Rats were pretreated with lactulose or vehicle for 2 days before treatment with Meth or saline. Rats were intracardially perfused with 10,000 Da FITC-dextran, 24 h after Meth or saline treatment. A) Representative 20X confocal images of FITC-dextran in cortical sections. B) Quantification of FITC-dextran indicates that Meth treatment significantly increased FITC-dextran extravasation (*, p < 0.05, compared to Vehicle Saline), which was blocked by lactulose pretreatment (#, p < 0.05, compared to Vehicle Meth) (n = 4–5 per group).