[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).

[Reactions of neural elements of neocortex on action of hypoxia at the early neonatal period in rats].

In this work we studied reactions of neural elements of various neocortex areas (sensomotor, visual, auditory) on action of acute normobaric hypoxia. The study is performed on the model of human premature pregnancy (action of normobaric hypoxia on rat pups at the 2nd postnatal day). There are revealed monotypical and monodirected structural reconstructions in all studied neocortex parts.

[Reactions of the interneuronal synapses of rat brain to hypoxia during the early postnatal period].

The reactions of forming synapses in rat neocortex to the effect of hypoxia in the early postnatal period (day 2) were studied. Using immunocytochemistry for synaptophysin demonstratoion and electron microscopic methods, the sensorimotor cortex was studied in rats at days 3, 4 and 10 of postnatal development (6 to 10 animals of each age) in both experimental and control groups (intact animals). Immunocytochemical study of the control animals demonstrated significant differences in the quantitative distribution of synaptophysin-positive structures in the different layers of the neocortex in the early postnatal period of development (day 5).

[Changes of the structural organization of the nucleus raphe pallidus after the decrease of endogenous serotonin level in the prenatal period of development in rats].

The role of serotonin in the nucleus raphe pallidus (NRP) development and the dynamics of its serotonin-producing neurons were studied during various time points of the postnatal period in normal Wistar rats and in animals developing prenatally under the conditions of serotonin deficiency. It was shown that NRP contained 2 populations of serotoninergic neurons with different morphological characteristics. At the initial stages of postnatal development (Day 5) serotonin-producing neurons included only large neurons, while the synthetic activity of small neurons appeared later (by Day 10).