[Ultrastructural characteristics of the intracerebral components of the blood-brain barrier].

Electron microscopic studies of interactions between the cerebral tissue, the basal membrane of intracerebral vessels, and the limiting superficial membrane have been carried out. It has been demonstrated that highly specialized contacts of the compact and gap type are maintained constantly between the membranes of the neighboring astrocyte spicules around the vessels and under the limiting membrane. Such contacts are also encountered in the intercellular space in the whole mass of the brain. It is suggested that this specialized system and the basal membrane are of importance for regulating the functioning of the hematoencephalic barrier. It is noted that there exists a united structured system at the border between the cerebral tissue, cerebrospinal fluid, and blood, the participates in the pathogenetic and homeostatic mechanisms.