[Neuronal porosome in the rat and cat brain].

It is well established that during cell secretion, membrane-bound secretory vesicles dock and fuse at the base of supramolecular cup-shaped structures at the cell plasma membrane called "porosomes", to expel intra-vesicular contents to the outside. In neurons, it has been demonstrated that 12-17 nm cup-shaped lipoprotein structure possessing a central plug are present at the presynaptic membrane, where 50 nm in diameter synaptic vesicles transiently dock and fuse to release neurotransmitter. In the past decade, the neuronal porosome has been isolated and its major chemical composition determined. Additionally, the porosome has been both structurally and functionally reconstituted into artificial lipid membrane, establishing its role as the secretory portal in neurons. Studies utilizing atomic force and electron microscopy, combined with electron density and 3D contour mapping, provide at the nanoscale, the structure and assembly of proteins within the neuronal porosome. In the current study, ultrahigh resolution imaging of the presynaptic membrane of isolated brains from both rats and cats, demonstrate for the first time, the presence of neuronal porosomes in cat brain, and further confirms the presence of porosomes at the presynaptic membrane in rat brain synaptosomes. Results from the present study further confirm the cup-shaped morphology of porosomes in the rat brain, and demonstrates their similar shape and size in the cat nerve terminal. The study also demonstrates for the first time, the universal presence of similar porosomes in different species of mammals.

[Porosome: a new organelle and the universal secretion machine in cells].

A new cell organelle, porosome, discovered in the mid 1990's and its demonstration as the universal secretory machinery in cells is described. In contrast to the generally accepted belief that the secretory vesicle membrane is totally incorporated into the plasma membrane during cell secretion, it has been shown that secretory vesicles transiently dock and fuse with the porosome base via SNARE proteins to expel vesicular contents under intravesicular pressure which is generated by active transport of water through water channels located at the secretory vesicle membrane.

[Quantitative analysis of gliocytes and macrogliocyte-neuronal ratio in the rat hippocampus after kindling].

Gliosis is one of the main morphological correlates of epilepsy. It is presented predominantly by proliferation and hypertrophy of astrocytes and activated microglia (macrophages) and is most characteristic to those areas of the epileptogenic zones, where the loss of neurons is significant. One of such structures is the hippocampus, the sclerosis of which develops already at the early stages of epileptogenesis. Using the slides stained with cresylviolet, the quantitative analysis of gliocytes and of macrogliocyte-neuronal ratio was performed in all the areas of the hippocampus 14 and 30 days after electrical kindling. After both time intervals, the decrease of the number of neurons and the increase of the number of gliocytes were found in all the regions of the hippocampus. After 14 days the changes of gliocytes were particularly significant in the radial and oriental layers of the Ammon's horn, after 30 days they were also pronounced in CA3 pyramidal cell layer of and in hilus. Thus, hippocampal gliocytes are actively involved in the epileptogenesis.

[Hippocampal cell loss in rats as a result of kindling].

Quantitative analysis was performed to evaluate the numbers of principal cells cells and interneurons in differenet layers and areas of the horn of Ammonis, hilus and dentate gyrus 2 weeks and 1 month after kindling--specific electrical stimulation of ventral hippocampus. After both experimental time intervals, a significant cell loss was found in all the layers and areas studied, with the exception of stratum oriens of CA4. Thus, in this model of experimental epilepsy, both interneurons and principal cells were found to be involved in the process of epileptogenesis. Different possibilities of reorganization of intrahippocampal circuits and their participation in increased excitability, typical to epilepsy, are discussed.

[The influence of myo-inositol on the ultrastructure of hippocampal CA1 area in kainate treated rats].

The ultrastructure of neurons, synapses and astrocytes of hippocampal CA1 area in rats was investigated 14 days after: systemic injection of kainic acid and kainic acid and myo-Inositol. After injection of kainic acid numerous neurons with superficial and deep ultrastructural changes of cytoplasmic organelles were described. Among synapses numerous forms with osmiophilic active zone and single synaptic vesicles, also presynaptic terminals with core vesicles were often seen. After kainic acid + myo-Inositol injection the cells with superficial changes of organelles dominated and the synapsoarchitectonics of the area was close to normal. Thus, electrono-microscopic data indicate possible neuroprotective (antiepileptic?) features of myo-Inositol.

[Cellular composition of the rat piriform cortex in experimental epilepsy].

Cellular composition of all the layers of anterior, central and posterior regions of rat cerebral piriform cortex was studied 2 weeks and 1 month after specific electrical stimulation (kindling) of ventral hippocampus through electrodes implanted one week earlier. According to the data of stereological analysis, following at both time intervals after kindling, all the layers in all the regions of piriform cortex demonstrated the significant decrease in numbers of interneurons and pyramidal cells. Three weeks after electrode implantation into the ventral hippocampus, the number of both pyramidal cells and interneurons was also found to be reduced in the central region of piriform cortex of rats in which stimulation had not been performed. The participation of piriform cortex in epileptogenesis is suggested on the basis of literature and personal data.

[Characteristics of structural organization of interneurons in CA 3 region and mossy fibers of hippocampus].

The paper reviews the current data on the structural peculiarities of the interneurons of hippocampal area CA 3. Special attention is paid to horizontal spiny interneurons located in the stratum lucidum and forming direct contacts with the system of mossy fibers. Their axons terminate at the proximal portions of dendrites and cell body of pyramidal neurons, occasionally they make contacts with the main cells of the hilus and other hippocampal interneurons. Some portion of axon collaterals is in close vicinity to direct and indirect entorhinal-hippocampal connections, indicating their accommodation to selectively suppress mossy fiber input. The latter form the synapses of various types on the principal cells and on various types of interneurons of area CA 3, indicating different mechanisms of transmitter uptake and presynaptic control of their release.

[Discovery of a new cellular structure--porosome].

A new cell structure--"porosome", discovered by the American scientist Bhanu Jena and co-wokers, is described. Mechanisms of budding and fusion of transport vesicle are elucidated in addition to those of fusion of secretory vesicles at the cell plasma membrane, and of release of intravesicular contents. The morphology of porosomes, their contents and functional reconstruction in lipid bilayer membranes were examined at a near nanometer resolution. Using atomic force microscopy, the presence of circular "pits", measuring 400-1200 nm in diameter with small 100-150 nm wide "depressions" inside and 3-4 deep pores, called porosomes, was demonstrated. A porosome is cup-shaped and 15-30 nm wide. Porosomes are the places where secretory vesicles fuse with the plasma cell membrane, and where the intravesicular content is released.

[The structure of the higher sections of the motor system in the rat brain after different forms of hypokinesia]. / Struktura vysshikh otdelov motornoi sistemy mozga krysy posle raznykh form gipokinezii.

Composition of structural elements and different types of glial cells of caudate nucleus head were studied after 40, 90 and 120 days of intensive and 90 days of non-stress hypokinesia. In small portion of neurons and synapses non-stress hypokinesia causes changes basically indicating their low activity while intensive hypokinesia leads to more significant disorders. Motor area retains almost normal structure in both forms of influence. Decrease of spine number and variability is characteristic. Number of neurons with satellites and separate satellite forms in intensive hypokinesia significantly increases in different cortical layers. Oligodendrocyte and astrocyte number grows appropriately in surface and deep layers.

[The ultrastructural reorganizations in the formations of the rat endbrain in decreased motor activity not evoking stress]. / Ul'trastrukturnye perestroiki v nekotorykh obrazovaniiakh konechnogo mozga krysy pri umen'shenii dvigatel'noi aktivnosti, ne vyzyvaiushchem stress.

Ultrastructure of central and lateral nuclei of amygdala, singular gyrus and caudal nucleus was studied in rats subjected to non-stress 90-days-long hypokinesia. Not numerous changes basically reflecting decrease of activity of a series of neurons and synapses were noted in all the formations. Selective nature of the action was demonstrated: in every region examined mostly one certain cell type changes. The data were compared with the results of earlier performed research concerning the action of "hypokinetic stress" on the same brain formations.

[The structure of the motor cortex in the rat in hypokinesia]. / Struktura dvigatel'noi kory mozga krysy pri gipokinezii.

Ultrastructure of neurons, synapses and glial elements was studied in the rat motor cortex under exposure to hypokinesia lasting for 40 and 90 days. Changes prevail in all cortical layers in 90-days hypokinesia and in upper ones in 40-days hypokinesia. These are basically reactive or not deep destructive changes. Cell elements and synapses with structural manifestations of low functional activity prevail with the increase of the experimental terms. Astrocyte number including satellite forms significantly grows in 40-days hypokinesia. In 90-days changes occur in all cortical layers with the increase of both astrocyte and oligodendrocyte number.

[The ultrastructure of the capillaries and pericapillary area in the formations of the rat forebrain in hypokinesia]. / Ul'trastruktura kapilliarov i perikapilliarnoi oblasti v nekotorykh obrazovaniiakh perednego mozga krysy pri gipokinezii.

Capillaries and pericapillary tissue were studied in central and lateral nuclei of amygdala, cingulate cortex, hippocampal fields CA1 and CA3 and sensomotor, cortex in rats, exposed to hypokinesia 40, 90 and 120 days lasted. Changes, growing more numerous and variable in proportion with the time of hypokinesia were found. The most essential changes were hypertrophy of glial elements with either decreased or increased functional activity. Alteration of the endotheliocyte structure, pinocytosis, hypertrophy and increase of nuclear and cytoplasmic osmophilia, decrease of the folding were noted. Capillaries with significantly increased folding and narrow or containing unidentified substance lumen were encountered in 120-days hypokinesia. In limbic structures pericapillary glia is represented mostly with astrocytes, in neocortex-also with oligodendrocytes.

[The ultrastructure of the myelinated fibers of the rat endbrain in hypokinesia]. / Ul'trastruktura mielinovykh volokon konechnogo mozga krysy pri gipokinezii.

Myelin fibres structure in phylogenetically different regions of telencephalon--in hippocampus, cingular cortex and sensomotor cortex of cerebrum of rats, in hypokinesia lasting for 40 and 90 days was studied electron-microscopically. Changes in ultrastructure of myelin fibres in these formations were found which exposed unequally in different regions and depended on the experiment duration. In 40 days hypokinezia changes were noted only in hippocampus and cingular cortex, while in neocortex they were prominent only in 90-days hypokinisia. Moreover, in neocortex changes were different in large and fine fibres, being more prominent in the former.

[An electron microscopic study of the quantitative characteristics of the neuronal and synaptic architectonics of the central and lateral nuclei of the amygdaloid body in the rat brain]. / Elektronno-mikroskopicheskoe issledovanie kolichestvennykh kharakteristik neirono- i sinapsoarkhitektoniki tsentral'nogo i lateral'nogo iader mindalevidnogo kompleksa golovnogo mozga krysy.

Some fine structural features of neurons and synapses in the central and lateral nuclei of rat's amygdala have been described. Neurons of the central nucleus are comparatively alike, but neurons of the lateral nucleus are distinguished by size, form and distribution of cell organelles. Different varieties of axonal profiles in both the nuclei are described. The axonal profiles are distinguished by quantity, form and localization of vesicles, presence or absence of an active zone, localization of profiles on different parts of neurons--soma, spines, fine dendrites and shafts. The axo-dendritic synapses were investigated quantitatively.

[The ultrastructure of the emotiogenic structures of the rat brain in a neurosis-like state acquired on a background of hypokinesia]. / Ul'trastruktura émotsiogennykh obrazovanii bol'shogo mozga krysy pri nevrozopodobnom sostoianii, vyrabotannom na fone gipokinezii.

The disorder of the higher nervous activity was induced in rats, situated for 90 days under the conditions of hypokinesia. Was investigated the ultrastructure of some limbic regions: the central and the lateral nuclei of the amygdala and area 24a of the cingulate cortex. Ultrastructural changes were seen in neurons, synapses, and the glial elements of the regions under study. The main characteristic of these changes was found to be the presence of morphological criteria of high functional activity in the majority of neurons and synapses. The results were compared with the previous data on the hypokinetic structural changes in the absence of a neurosis. In the latter case hypokinesia caused, on the contrary, the diminution of the functional activity in the majority of neurons and synapses under study.

[Effect of hypokinesia on the ultrastructure of emotion-controlling structures in the rat brain]. / Vliianie gipokinezii na ul'trastrukturu émotsional'nykh obrazovanii bol'shogo mozga krysy.

Hypokinesia lasting 40 and 90 days causes a number of ultramicroscopic reorganizations in neurons, synapses and glial elements of the singular cortex and the central amygdaloid nucleus. The longer the time of hypokinesia, the more numerous and variable the reorganizations become. For the amygdaloid body presence of neurons with various degree of chromatolysis, reactive and destructive changes of organells, agglutination and reduction in number of the synaptic vesicles, increasing number of synapses, possessing certain features of low functional activity are most specific. For the singular cortes are peculiar convolution of nuclear and cellular membranes, synaptic contact, increasing intercellular spaces, as well as changes in the structure of some axo-spine synapses, the spine apparatus including.

[Effect of social isolation on the ultrastructure of the dog brain]. / Vliianie sotsia'lnoi izoliatsii na u'ltrastrukturu golovnogo mozga sobak.

Ultrastructural changes in the central nucleus of the amygdalar body, field CA I of the hippocampus, piriform cortex, field 17 and field 7 have been studied in dogs, bred under conditions of social isolation. The changes are more numerous in emotiogenic structures. Similar ultrastructural rearrangements are revealed in the amygdalar body, hippocampus and in both fields of the neocortex. They are: neurons with different degree of chromatolysis, reactive changes in some organelles, terminals with agglutinated vesicles, or with their reduced number, increasing amount of synapses with a short active zone. At the same time, in the piriform gyrus vacuoles, membrane-like and osmiophilic inclusions, terminals with granular vesicles of various size are found more often.

[Connections between the posterolateral nucleus of the thalamus and the parietal and occipital areas of the cerebral hemispheres in the cat]. / O sviaziakh zadnelateral'nogo iadra talamusa s temennoi i zatylochnoi oblastiami polusharii bol'shogo mozga koshki.

A light optic and electron microscopic investigation on distribution of fibers from the thalamic posterolateral nucleus has been performed in the cat cerebral cortex. The fibers studied are revealed in the fields 7, 19 and 18. In the field 7 they are most numerous, comparatively seldom they are found in the field 19 and still more seldom--in the field 18. In the fields 7 and 19 identical peculiarities on distribution and termination of the fibers are noted: they spread across the whole cortex and end in all the layers with a predominant concentration in the layers III and IV. Most of the fibers make contacts on small dendritic branches and spines. In the field 18 the fibers are mainly limited by the medial layers and terminate predominantly on small, middle-sized dendritic branches, and comparatively rare--on the spines.

[Distribution of the fiber endings running from the superior colliculi of the tectum mesencephali into the visual projection zone (field 17) of the cat cerebrum]. / Raspredelenie okonchanii volokon, idushchikh iz perednikh kholmikov kryshi srednego mozga v zritel'noi proektsionnoi zone (pole 17) bol'shogo mozga koshki.

Distribution of fibrillar terminals, taking origin from the anterior colliculi of the midbrain tectum, in the central visual field 17 has been studied electron microscopically. Degenerating axonal terminals are detected in layers IV, V, VI and I. They are most numerous in layer IV. Most of them form contacts on small dendritic branches, at the same time, in layer IV other forms of degenerated interneuronal contacts occur rather often: on spiculae, on dendrites of larger diameter, in some cases,--on their main trunks. A suggestion is made that in the visual projection zone distribution and termination of the fibers taking origin from the anterior colliculi of the midbrain tectum are similar to the projection organization in other specific visual structure--the lateral geniculate body.