[REORGANIZATION OF THE ULTRASTRUCTURE OF NEOCORTICAL NEURONS IN RATS TREATED WITH CELL-FREE DNA].

Neuron ultrastructure was studied in layers III-V of rat brain neocortex 24 hours after intraperitoneal (n=3) or intravenous (n=3) injection of cell-free DNA (7.7x10(-5) g/kg body weight). A plastic restructuring of nuclear chromatin, nucleolar hypertrophy, deep invaginations of nuclear envelope, hyperplasia of mito- chondria and their close contact with other organelles and the nucleus, formation of cytoplasmic tubulovesicular bodies which may promote enhanced synaptic vesicle transport to presynaptic axonal terminals, activation of astrocyte glia were found.

[Fusion of brain neurons in rat embryos].

Syncytial interneuronal connections were studied in the sensomotor cortex and caudate nucleus of twenty 14-22 day rat embryos. It was shown that with the extremely weak development of glial processes, many neuronal bodies and their processes were in the direct contact with each other. The contacting membranes in these areas formed oblong and dot-like contacts resembling gap and tight junctions.

Synaptic plasticity of the neocortex of white rats with diffuse-focal brain injuries.

Studies on white mongrel rats addressed the reorganization of the synaptoarchitectonics of layer I of the cerebral cortex in diffuse-focal injuries. The experiments used models of acute arrest of the systemic circulation (clinical death) resulting from exposure to mechanical asphyxia for 6 min, clamping of the common carotid arteries for 20 min (ischemia), and imposition of sublethal rotatory trauma by the Noble-Collip method (craniocerebral trauma). Electron microscopy and morphometric analysis showed that reductions in the total number density of synapses were accompanied by changes in the relative and absolute contents of the major types of synaptic apparatuses.

[Synaptic plasticity of neocortex of albino rats in diffuse-focal injuries of the brain].

In an experiment conducted using mature albino rats, the regularities of reorganization of synaptic architectonics of cortical layer I of the brain were studied in the areas of diffuse-focal injuries. The models of acute break of systemic circulation (clinical death) as a result of 6-minute-long mechanical asphyxia, compression of common carotid arteries for 20 min (ischemia) and rotatory sublethal injury according to Noble-Collip method (cranial trauma), were used. Using the methods of electron microscopy and morphometric analysis, it was shown that a reduction in a general numerical density of synapses was accompanied by the changes in relative and absolute numbers of major variants of synaptic organization.

Structural-functional organization of neurons in the cerebral cortex of rats with different levels of resistance to emotional stress in conditions of exposure to delta sleep-inducing peptide.

Wistar rats with different levels of resistance to emotional stress (ES) were subjected to stress and brain sections stained with Nissl cresyl violet were used for quantitative analysis of the structural organization of neurons in layer V of the sensorimotor cortex. Some animals received delta sleep-inducing peptide (DSIP) 1 h before stress. Control ES-susceptible rats, as compared with resistant rats, had lower levels of normochromic and moderately hypochromic neurons.

[Structural and functional organization of the cerebral cortex neurons in rats with various resistance to emotional stress following administration of delta-sleep-inducing peptide].

In Wistar rats with different resistance to emotional stress (ES), subjected to stress exposure (SE), the structural organization of neurons in layer V of sensomotor cortex was studied quantitatively in brain sections stained using Nissl's cresyl violet method. One group of animals was injected with delta sleep-inducing peptide (DSIP) 1 hr before SE. In rats of control group predisposed to ES, the amount of normochromatic and moderately hypochromatic neurons was decreased as compared to the rats resistant to ES.

[Histological structure of adult mouse brain in protein-deficient nutrition].

The effect of protein deficient nutrition on histostructure of different regions of brain of mature animals was studied in the experimental model of protein and energy deficiency. Protein deficient nutrition was shown to exert negative influence on structural and functional state of brain neurons which is manifested through increase of dystrophic changes in neurons of all brain regions, accumulation of lipofuscine in neurons and complex of structural changes in synaptic contacts.

[Ultrastructure of human cerebral cortical synapses: age-specific aspects].

The paper deals with electron microscopic studies of the cerebral cortex in human beings aged 70-80 years. The synapses show a decrease in the number of synaptic vesicles, their impaired distribution in the presynaptic process. There are changes in the mechanisms of interaction of synaptic vesicles and a presynaptic membrane.

Structural and functional characteristics of neurons in the sensorimotor cortex of rats with different resistance to emotional stress.

Wistar rats behaviorally active in the open field test (resistant to emotional stress) are characterized by polymorphism of neurons in layer V of the sensorimotor cortex and the presence of hyperchromatic cells, which probably determines resistance to emotional stress in these rats. Atrophy of hyperchromatic neurons reflecting transient inhibition of cell activity was noted in Wistar rats subjected to stress. In the sensorimotor cortex of behaviorally passive animals (predisposed to emotional stress) groups of densely packed hyperchromatic cells and pronounced pericellular edema were revealed.

[Role of morpho-chemical plasticity in the genetic-functional organization of the brain in animals].

Quantitative cytochemistry has revealed that emotional stress-sensitive rats (August) differ from emotional stress-resistant ones (Wistar) in the exchange of neurotransmitters and in the level of protein in the neurons. The differences were found at the level of some brain regions (sensomotor cortex, hippocamp, caudate and adjacent nuclei) and various cells (neurons of the cortex and subcortical structures). It has been concluded that animals of genetically different lines differ not only in behavioral characteristics, but in metabolism in some brain structures.

[Synapse architectonics of the cerebral cortex in the evolutionary aspect].

The formation of synapses in ontogenesis is an important problem of neuromorphology. The paper shows that the bulk of synapses of the developing brain is formed on the basis of previous specialization of membranes. Early in ontogenesis, most formed synapses shows asymmetric contacts.

[Synapsoarchitectonics of cerebral cortex: ontogenetic aspects].

The formation of synapses in ontogenesis is an important problem of neuromorphology. The bulk of synapses of the developing brain is shown to be formed on the basis of prespecialization of membranes. In early ontogenesis, the bulk of the formed synapses represents asymmetric contacts.

[Changes in the ultrastructure of interneuronal connections in experimental chronic morphine poisoning].

To understand the mechanisms of brain activity and behaviour alterations in chronic morphine intoxication, it is especially important to analyze the changes occurring in the interneuronal connections. Analyzing cerebral cortical synapses during morphine treatment revealed that some new synapses formed. The newly formed synapses increased the total number of synapses of the cerebral cortex and reorganized synaptic architectonics.

[Changes in the configuration of the synaptic membranes in the human brain in aging and vascular pathology].

The structure of synapses in the brain of persons who had died of aging and vascular disease was studied by electron microscopy which indicated synaptic contacts with the convex and concave surface of pre- and postsynaptic membranes. There were also synapses with more complicated alterations in the configuration of synaptic membranes. The functional significance of the phenomenon is discussed in the paper.

[The mechanism of the development of the synapse as the basis for its involution].

The electron microscopic investigation of human brain synaptic organization in normal aging and in ischemic heart pathology in different life periods was performed. A significant quantity of desmosome-like and mixed contacts was shown. Their ultrastructural organization was similar to that of developing synapses during prenatal ontogenesis and in newborn rats.

[The ultrastructural reorganization of the neurons in some brain formations during the deprivation of paradoxical sleep].

Electron microscopy was used to study intracellular changes in the dorsal hippocampus, lateral hypothalamic nucleus and pontine reticular formation of rats after 96-hour paradoxical sleep deprivation. It was found that compensative-accommodative processes predominate in the majority of neurons. At the same time destructive changes are detected in some cells.

[Microvesicles in the developing synapses].

The sensomotor cortex and nucleus caudatus of the embryonal (14-22 days) and newborn rats have been investigated by electron microscopic method. There were described two groups of microvesicles (10-20 nm in diameter) with smooth and rough external surface. They differ from other vesicular components of the developing synapses (such as synaptic vesicles, vesicles of growing conus and other) by the minimal size, structure and localization.