[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.