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Biomedical subjects

L A Fedosikhina

Publications and source records attributed to L A Fedosikhina.

8 recordsLinked to original sources
PubMed1988

[Ultrastructural organization of the surface of the cingulate cortex of the cerebrum in rats].

In the cingulate cortex of rats the marginal glia is predominantly presented as fibrillar astrocytes, their bodies are situated immediately at the surface. Numerous axons, dendrites, synapses and myelinated fibers are often arranged near the very surface and are separated from it with only 1-2 thin processes of glial cells. Along the whole cortical surface one can see a limiting membrane--a layer of non-cellular substance, situating at the distance of 60-100 mcm from plasmalemmas of the marginal astrocytes. Using ruthenium red, it is possible to reveal the glycocalix layer on the surface of the limiting membrane, as well as cords of the electron opaque substance, that connect it with plasmolemma of the superficial astrocytes. Three types of the cingulate cortex surface are described in rats: superficial areas to which cells of the pia mater membrane adjoin; areas where cells of the pia mater membrane are situated at various distance from the cortical surface and areas of close adjoining of the right and left hemispheres of the cerebrum. Sometimes the cleft between the hemispheres is completely reduced, and narrow lamellar-like cells of the pia mater membrane are tightly inserted between the limiting membranes of both hemispheres or adjoin the blood vessel, situating between the hemispheres. At the surface numerous gap and desmosome-like junctions are observed. This is especially important at the border where the media are separated. At injection of neurotoxin 6-hydroxydopamine certain ultrastructural rearrangements are noted in cytoplasm of the marginal astrocytes, changes in the number and extension of intercellular junctions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

[Morphological restructurings in the brain due to a decrease in the catecholamine level].

Using light and electron microscopic examinations, the authors studied various portions of the rat brain following intracysternal administration of 6-hydroxydopamine. The lowered levels of noradrenaline in the cerebral tissue and an altered ultrastructure of neurons of the catecholaminergic centres and their processes were discovered in various areas of the brain. The time-course and the pattern of these readjustments may serve as a model for the investigation of the etiopathogenesis of various mental diseases and the elaboration of the methods of their pharmacotherapy.

Animals↗
PubMed1984

[Ultrastructural characteristics of the 1st cortical layer of the cingulate area of the brain in rats].

The limiting membrane, participating in formation of the liquor- and hematoencephalic barrier on the brain surface, and specialized intercellular contacts are considered as factors regulating entrance of substances from liquor and blood into the intercellular medium. Heteromorphism of the cingulate cortex first layer takes place: in the 1-b sublayer a large amount of myelinated fibres is revealed, in the 1-c sublayer numerous longitudinal sections of dendrites are seen, they arrange perpendicularly or tangentially to the brain surface. In the 1-a sublayer, more often than in others, multifocal axodendritic synapses are observed they are of convergent or divergent types, several synapses occur. In the first layer of the cingulate cortex, axonal profiles are revealed, they resemble axons of the neurosecretory cells described in the literature. This cannot exclude any hormonal mechanisms affecting the neurons of the cingulate cortex. Numerous synaptic contacts, formed by afferent fibers that come from different brain structures, with processes of the first layer cells and ascending dendrites of deeper layers are considered as a morphological substrate of integrative and modulating activity of the first layer.

Animals↗
PubMedDate not supplied

[Reaction of neurons of the cerebral cingular area in rats to damage of the central monoaminergic systems].

Intracisternal injection of specific neurotoxins 6-oxydopamine and 5,7-dioxytryptamine, producing certain disorders in catecholaminergic and serotoninergic systems respectively, is accompanied with some ultrastructural rearrangements in the proper neurons of the rat cerebral cingular cortex. In the experimental material an essential increase in the amount of intranuclear inclusions--vacuole- and myelin-like--of fibrillar origin is observed. More often than in the control connection of the endoplasmic reticulum with the nuclear membrane is noted. Hypertrophy of cisterns in the Golgi complex, abundance of coated vesicles in its region, dilatation of cisterns of the endoplasmic reticulum are observed. The character of the ultrastructural rearrangements demonstrates certain changes in activity of metabolic processes of these cells, the changes being more pronounced in the case, when the cerebral serotoninergic system is damaged. The reaction of the cerebral cingular zone to injection of neurotoxins is characterized with a selective manifestation and is restricted with certain nervous cells of the II-V layers. According to their ultrastructural organization, these neurons can be considered as stellate and pyramidal.

5,7-Dihydroxytryptamine↗
PubMedDate not supplied

[Subcellular changes in the cortex of the motor analyzer and hippocampus of dogs with locally manifested neuroses].

In experiments on dogs with local neurosis-continuous flexion of the foreleg-changes were revealed in the beta-rhythm amplitude and the frequency of mean unit activity in the motor cortex, and the appearance and increased amplitude of the theta-rhythm in the hippocampus. Specific activity of Na+-K+-activated, and Mg2+-dependent ATPase decreases in subcortical fractions of the experimental animals' cerebral cortex by 55.0% in the synaptic membranes and 2 to 2.5 times in light and heavy synaptosomes, respectively. In similar fractions of the dorsal hippocampus, the activity of the enzyme decreases by 30.0% in the synaptic membranes and increases by 16.6% in the light synaptosomes and by 6.6% in the heavy ones.

Adenosine Triphosphatases↗