Abstract
The notion that a static blood–brain barrier (BBB) controls the rapidly changing brain environment is obsolete. Not only have we recognized the role of the BBB in maintenance of brain homeostasis, but we have also accepted the pivotal role that BBB dysfunction plays in many neurological diseases. The neurovascular unit and its barrier components have been implicated in leukocyte extravasation, inflammation, generation of seizures and psychosis, and multidrug resistance. In addition, the ways in which the BBB mediates the establishment of cerebral edema, metastatic invasion, and stem cell trafficking are now at least partially understood. In this chapter, we recapitulate the historic pathway that led us to the current level of understanding and underscore modern challenges in the field of BBB research. We also describe the advancements in clinical and preclinical neurosciences achieved by progress in BBB research.