Percent uptake of PF-lip, PFTf-lip, R9F2-lip and R9F2Tf-liposomes in (A) bEnd.3, (B) glial and (C) primary neuronal cells after 0.1, 0.25, 0.5, 1 and 4 h of incubation. Percent uptake of PF-lip, PFTf-lip, R9F2-lip and R9F2Tf-liposomes after 4 h of incubation in (D) bEnd.3, (E) glial and (F) primary neuronal cells pretreated with endocytosis inhibitors (sodium azide, chlorpromazine, amiloride and colchicine). Data are expressed as mean ± SD (n=5).