Abstract
Epithelial tissues divide external environment and internal milieu to maintain homeostasis. Tight junctions (TJ) are one mode of cell to cell contacts apparatus in epithelia, which control paracellular permeability of epithelial cellular sheets. The major components of TJ are claudins, that have tour transmembrane proteins and consist of multi-gene family. The blood- brain barrier (BBB) has a crucial role for maintaining homeostasis of CNS. TJs that exist in endothelial cells in brain microcapillary characterize barrier function of the BBB. To date, it is suggested that dysfunction of the BBB is involved in many neurogenic disorders. In developing drug delivery strategies, BBB- forming endothelial cells are promising therapeutic targets.
