[The translocation of macromolecules via the hematoencephalic barrier]

The solution to the problem of transportation of high-molecular substances via the hematoencephalic barrier (HEB) is a necessary condition for the development of theoretical and applied aspects of selective transport of biologically active substances (neurotrops, medications) from blood into the brain. In the last decades, views on the possibility of macromolecular transport through intact HEB have changed substantially. Under physiological conditions, translocation of macromolecular substances via HEB is performed with the help of specific molecular transport systems and by endocytosis. The former mechanism prevails both in intensity and the nomenclature of the substances transported. The permeability of the intact (unchanged) HEB for macromolecules exists to an extent necessary for normal CNS functioning. Destruction of dense contacts in the HEB, local retraction and death of endotheliocytes, destruction of the basal membrane take place in pathological processes in the nervous tissue under the influence of inflammatory factors (cytokines, metalloproteinases etc) induced by activated endotheliocytes, T-lymphocytes, macrophages and glial cells; this in fact opens the paracell way for macromolecular components of blood.