Mammalian brain is protected against the ingress of ions and various substances circulating in the blood by a special type of vascular network which is a habitat on blood brain barrier (abbreviated BBB) . The objective of this paper is to present the current state of knowledge on the distribution of protein components of intercellular endothelial brain that maintain the tightness of the barrier. Of these calls there are two basic types: the connection fitting , known in scientific literature as adherens junctions English language ( AJs ) and tight junction ( barrier ) known as tight junctions ( TJs ) . Each call type has specific protein components of the arrangement of which at the level of the ultrastructure of brain sections examined in mouse, rat and man using immunocytochemical methods using colloidal gold -labeled antibody and electron microscopy. The main focus in this paper is given to the presence and distribution of both internal ( membrane connecting adjacent cells , or transmembrane proteins ) proteins typical of the tight junction ( TJs ) : okludyny , Klaudyny and JAM, and typical of adherens junctions ( AJs ) : cadherins , as also called. Peripheral proteins represented by protein closure zone ( zonula occludens - 1 , or ZO- 1 , mainly in TJs ) and catenin ( adjacent connections , AJs ) . This latter group of proteins connects the inner peripheral proteins actin cytoskeleton of mikrofilamentami . The results indicate that both types of connections are arranged next to each other ( alternate ) in the vascular endothelium of representing BKM . However, only a protein associated with tight connections , such as occludin and optionally together with a peripheral Klaudyna ZO- 1 protein may serve as markers (indicators ) useful in contrast to the normal or impaired renal vascular brain barrier .