Biomedical subjects

N N Bogolepov

Publications and source records attributed to N N Bogolepov.

At least 19 recordsLinked to original sources

PubMed2006

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. There were increases in the numbers of large simple and perforated contacts and synapses with invaginated synaptic membranes, mitochondria, and spine apparatuses. These changes were interpreted as the structural basis for the mechanisms of synaptic plasticity in diffuse-focal brain injuries.

Animals↗

PubMed2005

[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. The content of large simple and perforated contacts was increased, as well as of synapses with invaginated synaptic membranes, containing mitochonria and spine apparatus. The changes detected are considered as a structural basis for realization of the mechanisms of synaptic plasticity in diffuse-focal injuries of the brain.

Animals↗

PubMed2004

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. Normochromic neurons were not seen after stress. Rats susceptible to ES showed particularly sharp decreases in moderately hypo- and hyperchromic neurons, along with increases in the proportions of extremely hypo- and hyperchromic neurons, ghost cells, and ischemically altered cells. After administration of DSIP before stress, ischemically altered cells were not seen in any group: the level of reduction of extremely hyperchromic neurons was smaller in ES-susceptible rats than in ES-resistant rats. It is suggested that brain hypoxia plays a particular role in disorganizing the cortex in conditions of ES, while DSIP has both antistress and antihypoxic properties.

Adaptation, Psychological↗

PubMed2003

[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. After SE, normochromatic neurons were not demonstrated. In rats predisposed to ES, the contents of moderately hypo- and hyperchromatic neurons was found to fall dramatically with a simultaneous increase in the number of extremely hypo- and hyperchromatic neurons, ghost cells and ischemically changed cells. After DSIP infusion before SE, ischemically damaged cells were not found in any group, while the degree of shrinkage of extremely hyperchromatic neurons was lower in rats predisposed to ES as compared to rats resistant to ES. It is suggested that brain hypoxia plays an important role in cortex disorganization during ES, whereas DSIP, possesses both antistress and antihypoxic effects.

Animals↗

PubMed2002

[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. In the latter, the vesicles loose their discreteness, some of them are replaced by a fine-granular material. The joining of the vesicles and membrane is impaired. A part of active synaptic areas is transformed to desmose-like contacts. The findings are indicative of synaptic dysfunction.

Adult↗

PubMed2001

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. In these rats stress caused irreversible changes in cortical neurons and death of some cells. The presence of ischemic cortical neurons in rats subjected to emotional stress suggests that cerebral hypoxia plays a role in structural and functional disorganization of the sensorimotor cortex during emotional stress.

Animals↗

PubMed2001

[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. In postnatal ontogenesis, the formation of synapses proceeds due to the simultaneous occurrence of specialization of membranes and synaptic vesicles, by forming a "dot" active zone. Systemogenesis, such as the general law of brain development, plays an important role in understanding the functional significance of the shown mechanisms of maturation of synapses.

Age Factors↗

PubMed2001

[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.

Acetylcholinesterase↗

PubMed2000

[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.

Animal Nutritional Physiological Phenomena↗

PubMed1999

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. In postnatal ontogenesis, a synapse forms due to the simultaneous occurrence of specialization of membranes and synaptic vesicles by forming an active "dot" zone. Systemogenesis, such as the general law of brain development plays an important role in understanding the functional importance of the mechanisms of synaptic maturation.

Animals↗

PubMed1998

[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. The changes in the synaptic architectonics accompanied ultrastructural changes of dendrites. The development of new synapses and changes of dendrites are the basis for the formation of pathological cerebral cortical systems.

Animals↗

PubMed1998