[Development of blood-brain and blood-cerebrospinal fluid barrier (author's transl)]

In this article, the author reviewed the world literatures concerning the development of blood-brain (BBB) and blood-cerebrospinal fluid barrier (BCSFB) in both humans and animals. The author also briefly reviewed the results of his investigations on the development of these barriers to horseradish peroxidase (HRP) in chick embryos. The barriers to water-soluble macromolecules are likely to develop almost completely before birth in humans as well as in experimental animals. However, the timing of their completion is different between BBB and BCSFB. This may reflect the different nature of the tight junctions between capillary endothelial and choroidal epithelia. BBB and BCSFB to lipid soluble substances, water-soluble low molecular particles and electrolytes develops in different manners and timing. Development of selective barrier or transport system of metabolically active substances such as D-glucose or essential amino acids may be roughly synchronous to the maturation process of the brain and become fully effective after complete evolution of BBB and BCSFB to macromolecules. To study development of BBB and BCSFB is of great importance for understanding the pathogenesis of kernicterus and various CNS malformations.