ABSTRACT
The brain capillary endothelium possesses a number of receptors which allow the transport of specific materials. These include small molecule nutrient receptors, such as those for hexose, amino acids, amines, and a number of peptide and protein receptors, including those for insulin, transferrin and IGF-II26. It is possible to take advantage of these pathways for the delivery of mimetic drugs; for example, dopamine is poorly transported through the blood brain barrier, and its administration is of no direct therapeutic value, but the aminoacid analogue L-DOPA is transported through the phenylalanine receptor and can thus exert a useful pharmacological effect27.
