Blood-Brain Barrier

Abstract

Blood-brain barrier, the tightest barrier in the body located between the blood and brain, is composed of endothelial cells, basal membrane cells, and glia limitans consisting of pericytes and astrocytes; with tight junctions in between. The blood-brain barrier was believed to be a static structure, but now it is known to be a dynamic structure. Primary function of the blood-brain barrier, which acts tike a separator between the intravascular compartment and the central nervous sytem, is to form and protect the homeostasis within the central nervous sytem. Brain endothelium tightly regulates and modulates the infiltration of the plasma components and the cells in circulation. The specific and characteristic features of the cerebral endothelial cells limit the permeability of the blood-brain barrier. lf the blood-brain barrier is damaged, central nervous system will be exposed to the humaral neurotransmitters and plasma components that disturb the functioning of the central nervous sytem. Under normal circumstances, cerebral endothelial cells separate the brain parenchyma and the cerebral vascular compartments, and only active immune cells are allowed to pass this barrier. This feature of the central nervous sytem plays an important role in the immune-mediated disorders, tike multiple sclerosis.