Molecular biology of the blood-brain barrier.

Molecular biological investigations into the brain capillary endothelium and microvasculature, which forms the blood-brain barrier (BBB) in vivo, can provide the platform for the discovery and the molecular cloning of BBB-specific genes. Novel BBB genes can be discovered with either a genomics-based approach such as subtractive suppressive hybridization, or a proteomics approach using subtractive antibody expression cloning. BBB-specific genes are disproportionately transporter genes encoding either for carrier-mediated transporters, active efflux transporters, or receptor-mediated transporters. The discovery of new BBB transporters can lead to the development of new approaches to brain drug delivery using endogenous brain endothelial transporters.