[REACTION OF STRUCTURAL ELEMENTS OF HEMATOENCEPHALIC BARRIER IN NEWBORN RATS TO NORMOBARIC HYPOXIA].

For the last time a particular interest of investigators has been attracted to the period of early newborn state when active process of adaptation of the organism to new life conditions occur defining its increased sensitivity to the effect of unfavorable environmental factors. An important place among these processes belongs to formation of homeostasis mechanisms and, primarily, the barrier mechanisms. The purpose of the present study was to investigate reactions of the hematoencephalic barrier (HEB) to action of perinatal normobaric hypoxia (a model of incomplete human pregnancy). Using light and electron microscopy, our investigation showed that after action of hypoxia all wall elements of neocortex capillaries revealed structural alterations which may cause impairment of microcirculation and increased permeability of HEB. It is established that differentiation of the basal membrane of a capillary wall takes place during the early perinatal period and the indicator of its differentiation is the formation of its plates - laminae rara et densa. After action of hypoxia, besides a delay of formation of the basal membrane, a vesicular type of its degeneration occurs. Key words: perinatal hypoxia, hematoencephalic barrier, capillary, endothelial cells, basal membrane.