[The structure of rat pinealocytes in stress and after unilateral intranasal administrations of oxytocin]. / Struktura pinealotsitov krysy pri stresse i posle unilateral'nykh intranazal'nykh vvedenii oksitotsina.

Stress-induced functional changes in the light pinealocytes and signs of stress-limiting effect of oxytocin were revealed in white non-linear rats. The data obtained suggests involvement of oxytocinergic systems in the stress modulation of pinealocytes.

[The reaction of the neocortical structures in the seal Pusa sibirica to a prolonged stay under water]. / Reaktsiia struktur neokorteksa nerpy Pusa sibirica na dlitel'noe prebyvanie pod vodoi.

Using light and electron microscopic techniques, structural and functional changes in the neurones and glia of the Baikal seal neocortex were revealed during diving. These changes include shifts in tinctorial properties of cells, in the number of dendritic spines, cell ultrastructure (condensation and redistribution of nuclear chromatin, swelling of organoids, etc.). These changes are both non-specific and reversible, indicating high reserve capacities of the brain in this species.

[The structural characteristics of the auditory portion of the cerebral cortex in the Baikal seal (Pusa sibirica) and the neuronal reaction to hypoxia]. / Strukturnaia kharakteristika slukhovogo otdela kory bol'shogo mozga baikal'skogo nerpa (Pusa sibirica) i reaktsiia neironov na gipoksiiu.

Methods of light (Nissl, Golgi-Kopsch) and electron microscopy were used for studying the structural organization of the auditory portion of the cerebral cortex of Pusa sibirica. The auditory port of this kind of cortex is characterized by pyramidization of all the layers (layer IV included), thick layer I, two sublayers in layer III which is typical of other semiaquatic and aquatic mammals. Synaptoarchitechtonics of this part of the neocortex may be compared with that of other aquatic, semiaquatic and terrestrial mammals. The investigation of the state of neurons of the auditory portion of the cortex of Pusa sibirica during induced 18-min hypoxia has shown that the alterations in the neurons are of functional and reversible character. The axosomatic synapses remained most intact. The alterations in the auditory portion of the neo-cortex of Pusa sibirica evidences high level of adaptive reactions to hypoxia associated with the adaptation of these mammals to diving and fixed in the evolutionary process.

[Structure of the endotheliocytes of cerebral vessels of aquatic mammals]. / Struktura éndoteliotsitov krovenosnykh sosudov mozga vtorichnovodnykh mlekopitaiushchikh.

By means of scanning microscopy the relief of luminal surface of endotheliocytes, lining microvessels of various parts of the brain in the Pusa sibirica, Phoca vitulina and Delphinapterus leucas have been studied. Specialized formations of the cellular surface--various processes, projections, toruli have been revealed; their character in various parts of the brain in diving animals is determined by the blood stream conditions and their different sensitivity to oxygen deficiency during diving. The peculiarities, revealed in the structure of the cerebral vessels intima, are considered as one manifestations of the adaptive properties in the organism of diving animals, which had been developed in them during the process of a long evolution, while they adapted to the aquatic environment.

[Structure of the neocortex of the Baikal ringed seal (Pusa sibirica Gm.)]. / Stroenie neokorteksa baikalskoi nerpy (Pusa sibirica Gm.).

The sulci and gyri of the neocortex, as well as cyto-, synaptoarchitectonics and neuronal composition of the sensomotor (brain area) have been studied in the Baikal ringed seal. The structure of the sulci and gyri have been found to be similar to that in carnivores. The following specific features have been revealed in the brain of this endemic species: a thick layer I, presence of giant pyramidal cells in the layer III, large mitochondria in the presynaptic parts and dendrites. The results obtained are discussed concerning adaptation to semiaqueous way of life and to diving.

[The ultrastructure of the spines on serial sections of the rat cerebral cortex]. / Ul'trastruktura shipikov na seriinykh srezakh kory mozga krys.

Electron microscopy was used for studying in detail the structure of dendritic spines of cortical neurons in layer III of the rat's sensomotor cortex. It is found that the electron-dense substance between the cisterns of the spine apparatus consists of orderly arranged fibrillae. Serial sections allowed to follow the changes in the spine apparatus, in the curvature and intermittent character of the synapse active zone, as well as the connection between the cisterns of the spine apparatus, and between these and other membrane structures of the spine. The correlation is shown between the dendrite diameter and the shape and size of the spine.