Tight Junctions and the Blood-Brain Barrier

Abstract

The blood-brain barrier protects the neural microenvironment from changes of the blood composition. It is located in the endothelium which is both seamless and interconnected by tight junctions. The restrictive paracellular diffusion barrier goes along with an extremely low rate of transcytosis and the expression of a high number of channels and transporters for such molecules which cannot enter or leave the brain paracellularly.