Caffeine blocks high cholesterol diet-induced extravasation of IgG. (A) Cholesterol-enriched diet increased extravasation of IgG in olfactory bulb and this effect was blocked by caffeine at the dose of 3 mg/day. Caffeine alone had no effect on extravasation of IgG in normal rabbit brain. Representative images taken from 2 rabbits in each group with 6 sections from each animal are shown. Bar = 50 μm. (B) Cholesterol-enriched diet significantly increased accumulation of IgG in olfactory bulb and this effect was blocked by caffeine at the dose of 3 mg/day. (C) Neither cholesterol-enriched diet nor caffeine changed significantly plasma levels of IgG. n = 4, *p < 0.05.