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The aim of the study was to establish the dependence of memory processes and learning ability in gamma-irradiated white mice on the age and period after irradiation. The 3-month and 1-year-old male mice (Mus musculus) were used in the study. Mice whole-body irradiation was performed at a dose of 5 Gy with 137Cs by using a "Gamma-capsule-2". Spatial learning and formation of memory were estimated in the elevated-type multi-way maze and elevated plus-maze. Experiments were carried out 48 hours and 30 days after irradiation for seven days (five trials each day). The number of errors (deviations from optimal trajectory) and total time for crossing the maze were calculated. The results of the study indicate that ionizing irradiation with a total dose of 5 Gy results in a delayed spatial learning process, causes spatial memory and behavior changes in different age groups of animals - aged mice turned out to be more radio-resistant. Age-related radio-resistance plays an especially major role in the early stage of post-radiation recovery. Though, the late radiation aging effect is especially pronounced in young animals.

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Disorders of neurogenesis of cortical and subcortical structures in rat brain limbic system were studied in the offspring of rats that received ethanol during pregnancy. The methods used included the staining of histological sections with cresyl violet, in vitro culture, and electron paramagnetic resonance. Prenatal alcohol intoxication was shown to induce the disturbances in proliferative activity of granular layer cells in the hippocampal dentate gyrus, neuron- and glioblast migration, enhancement of free NO and lipoperoxide production and cell death. This resulted in the changes in the number of neurons in cortical and subcortical structures of rat brain limbic system and in fetal alcohol syndrome formation.

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The aims of the present work were to measure neuron density in the limbic cortex in the offspring of female white rats given 15% ethanol solution during pregnancy and lactation and to address the possibility of correcting ethanol-induced impairments at the early stages of postnatal development (PND) using the antioxidant Dolivin. Neuron numbers were measured in the cingulate gyrus and entorhinal cortex on PND days 3, 7, 15, 21, and 30 (three animals in each age group). Dolivin (0.7 mg) was added to the diets of female animals with the aim of preventing ethanol-induced changes. The cytotoxic action of ethanol was found to decrease the total number of cells in the limbic cortex at the early stages of PND, particularly on day 7. Neurons in the deep part of the limbic zone were the most sensitive to the actions of ethanol. Dolivin had preventative effects, weakening the cytotoxic actions of ethanol at all stages of development.

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The oxidative stress-induced alteration in concentration of oxygen, lipid and nitrogen free radicals in cultured brain cortex of the newborn albino rats and its correction with vitamins E and C was investigated. Modeling the oxidative stress was achieved with addition of H(2)O(2) into the nutrient medium. In order to prevent an oxidative stress-induced cytotoxic effect, concomitantly with H(2)O(2), vitamins E and C were added into the nutrient medium. Oxygen, lipid and nitrogen free radicals were registered by method Electron Paramagnetic Resonance (EPR) and spin-traps. The data, obtained in our study revealed decreasing of intensity of NO content and increasing of spin trapped superoxid- (O(2-)) and lipoperoxid-radicals (LOO.) in explants of brain cortex of the newborn albino rats cultured in oxidative stress conditions. These changes were attenuated following action of vitamins E and C (decreasing of intensity of EPR signals of O2- and LOO, increasing of free NO content).

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The purpose of this study was to determine the density of neuron disposition at the early stages of postnatal development of limbic cortex in the offspring of female rats, that consumed 15% ethanol solution during pregnancy and lactation period instead of water, and to detect the possibility of the correction of ethanol-induced changes with antioxidant Dolivin. The number of neurons in the cingulate girus and entorhynal cortex was determined at different stages of postnatal development (postnatal days 3, 7, 15, 21, 30). With an aim to correct ethanol-induced disorders, alcoholized females for the similar period of time, were given Dolivin (0.7 mg daily). It was shown that the cytotoxic effect of ethanol resulted in the decrease in the neuron numbers at the early stages of postnatal development, particularly at day 7. The neurons most sensitive to the ethanol action were observed in the deeper limbic cerebral cortex. The application of Dolivin has demonstrated its preventive effect, by weakening the ethanol cytotoxicity at the all stages of postnatal development.

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The oxidative stress-induced changes and feasibility of prevention of these changes with an aid of vitamines E and C were investigated in cultured brain cortex of the newborn albino rats. Modeling the oxidative stress was achieved with addition of H(2)O(2) into the nutrient medium. In order to prevent an oxidative stress-induced cytotoxic effect, concomittantly with H(2)O(2), vitamines E and C were added into the nutrient medium. The data, obtained in our study revealed inhibition of the glial cells'- and axonal migration into the growth zone resulting from the oxidative stress. These changes were attenuated following action of vitamines E and C, which points at feasibility of their use against oxidative impact from the free radicals emerging during neurodegenerative disorders.

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The number and weight of cells in the cortical and subcortical structures of the cerebral and cerebellar motor system in albino rats after a long-term exposure to toluene. Toluene intoxication proved to kill projection neurons and interneurons in the sensorimotor cortex, ventrolateral thalamic nucleus, caudate nucleus, pallidum, red nucleus, and inferior olivary complex. The decreased number of cerebellar cells was mediated by atrophic changes as indicated by the decrease in the area and dry weight of Purkinje cells. The addition of plaferon LB to the diet attenuated the cytotoxic effect of toluene.

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Metabolic processes in the brain cortex of albino rats with prenatal and postnatal alcohol intoxication were studied by the method of electron paramagnetic resonance. Accumulation of superoxide radical-generating agents, inactivation of superoxide dismutase, and increase in nitric oxide concentration were detected. Activation of free radical processes was associated with accumulation of Mn(2+)and Fe(2+). The parameters of electron paramagnetic resonance returned to normal after Dolivin treatment. These changes were accompanied by a decrease in the intensity of oxidative metabolism.

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We studied the effect of ethanol on the growth and differentiation of spinal cells in 14-day chick embryos in vitro and the possibility of correcting the destructive changes with dolivin (antioxidant). Ethanol blocked migration of glial cells and growth of axons. Addition of dolivin into the nutrient medium together with ethanol prevented the effect of ethanol and stimulated axon growth and migration of glial cells.

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Study of stimulating effects of human umbilical cord blood serum supernatant of chicken embryo somatic muscle tissue, and dalargin on the differentiation of chick embryo spinal neurons under conditions of cultivation has revealed that the highest stimulating effect is exerted by human cord blood serum at increased concentration (20%), promoting intensive growth and differentiation of axons and dendrites of spinal neurons. The stimulating effect of the serum has also been observed during cultivation of individual explants, when the influence of the factor responsible for activation and direction of the growth of axons and dendrites during simultaneous cultivation of two explants is excluded.

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To determine species-specific cells in mixed culture, obtained after simultaneous cultivation of dissociated cells of chick embryo midbrain tegmentum and newborn albino rat cerebral cortex, various DNA amounts were used for testing chick and rat cells. The study of cell structure of the aggregates revealed that in addition to the aggregates consisting of cells belonging to only one species of animals, chimera aggregates also exist made of cells of both species of animals, basically of chick embryo glial cells and newborn rat neurons.

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Peculiarities of the axons growth in the culture of 14-day old chick embryo spinal cord after 24, 48 hr, 3, 5 and 7 days in the Maximov's chamber were observed. For the stimulation of axon growth the spinal cord was cultivated simultaneously with the explants of the muscle tissue and in the medium after the addition of supernatant of the somatic muscle. It has been demonstrated that the growth of the axons stimulated with the muscle explants or muscle supernatant takes place through the growth cones, while in the absence of growth stimulation effect glial cells can take part in the axons growth. It is supposed that the glial cells are capable of playing the role of the cells, which direct axons growth in the absence of influence of specific target factor.

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Different types of changes in glial cell reactions in organic and monolayer cultures are described. These changes are shown to reflect the behaviour of glial cells in vivo. A special attention is paid to the role of glial cells in the axon growth, and to their contractile activity and alterations under cytotoxic edema conditions. The establishment of intercellular contacts is shown to provide the general reaction of a group of glial cells.

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A study of the ultrastructural peculiarities of the spinal cord neural cells in 14 day old chick embryos at the early stages of cultivation has shown that adaptation processes are completed within the first days of explant cultivation. Further cultivation leads to the differentiation of neurons and to the recovery of their capacity of bioelectrical activity.

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Numerous axons of associated cells were found in the cultures of 13-day old chick embryo spinal cord. These axons formed loops, while leaving the explants, and returned into the cultivated piece. This phenomenon can be due to pronounced specific influence of the explant on the growth of axons of the associated cells via the motoneurons which play the role of target cells.

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A study of features of behaviour of nerve and muscle cells of the chick embryo spinal cord and skeletal muscles, with their simultaneous cultivation, has shown the growth of nerve fibers from explants of the spinal cord towards the muscle tissue. It was also found that muscle fibers were growing intensively to be represented as symplasts. On the basis of these data, a conclusion can be drawn that despite the complete differentiation of the nerve-muscle synapse of the 13 day old chick embryos, the cultured nerve cells maintain the capacity of the oriented growth and formation of the efferent junctions between the explants of the spinal cord and somatic muscles.

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The amount of DNA and the dry weight of the nuclei of cells of the external geniculate body, as well as the photoreceptor, bipolar, and ganglionic cells of the retina of the eye, were studied at the early stages of postnatal development of guinea pigs by the methods of cytospectrophotometry and interferometry on prints of the tissue. In the photoreceptor and bipolar cells of the retina, a stable, diploid amount of DNA is detected. In the ganglionic cells and nerve cells of the external geniculate body, in addition to the diploid cells a small group of tetraploid cells was detected. The dry weight of the nuclei of the external geniculate body and retina increased appreciably on the third day of postnatal development.

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