fig1

Figure 1. Mechanisms of transport across the blood-brain barrier. (1) Transcellular diffusion (small hydrophobic molecules); (2) paracellular diffusion (small water soluble molecules); (3) carrier-mediated transport (e.g. glucose, amino acids, vinca alkaloids); (4) active efflux transport; (5) receptor-mediated transport (e.g. insulin, leptin, transferrin); (6) adsorptive-mediated endocytosis (e.g. albumin, plasma proteins). ATP: adenosine triphosphate