Figure 2.

Localization of ATP-Binding Cassette (ABC) transporters at the Blood-Brain Barrier (BBB). ABC efflux transporters that are known to play a critical role in central nervous system (CNS) drug disposition are shown. All of these transporters function as primary active transporters and utilize ATP as an energy source to move drug molecules against their concentration gradient. Current knowledge in the field implies that P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP) function in synergy to restrict blood-to-brain transport of therapeutics [6,69].