Vol 138, No 6 (2010)

To solve the problem of the possibility of syncytial connection in the nervous system, this paper for the first time presents the evidence of experimental syncytial fusion of neurons. Neurons, isolated from the ganglia of the mollusc Lymnaea stagnalis and freed from the surrounding glia by pronase treatment, were drawn together by centrifugation and were kept in the culture medium for two days in the aggregated state. The neurons preserved the ability to generate normal processes. At the borders of adjacent cells, contacting mutual protrusions (feet) were formed that were separated from each other by vacuole-like enlargements of the intercellular clefts. Using the electron microscope, it was shown that at the borders of contacting feet the external cell membranes were destroyed. Only residual fragments of the destroyed membranes were detected. The cytoplasm of one adjacent cell was continuous with the cytoplasm of the other. Thus, the experiments confirm once more the correctness of the cell theory concerning the common main properties of all the cells and expand the concepts of the neuronal theory by the statement that in the nervous system, along with chemical synapses and electrical membrane contacts, the syncytial interneuronal connections are also possible.

The purpose of this study was to investigate the long-term reactive changes in the subventricular zone (SVZ) of the rat brain lateral ventricles after the intraventricular injection of betaamyloid peptide (BAP). It was found that 3 months after BAP injection ependymal cells and SVZ cells reacted to the intraventricular BAP injection by the formation of glial structures, similar to amyloid plaques in their composition, cell structure and possible developmental mechanism. Using immunohistochemical methods, it was shown that they consisted mainly of reactive astrocytes and microgliocytes. It is suggested that atypical morphogenesis of these structures is associated with the interrelationship between the degenerative and regenerative processes, which involve both ependymal cells and forebrain proliferative zone progenitor cells.

The purpose of the present research was to study the peculiarities of topography and structure of cranial mesenteric lymph nodes of newborn rats that were prenatally exposed to ethanol during their development. Female rats received 15% ethanol solution for 1, 2, 3, 4, 5 and 6 months preceding pregnancy and throughout it. Morphometric and routine histological methods were used. The number of lymph nodes and their cross-sectional area in the newborn rats were changed depending on the duration of maternal pregravid ethanol exposure. The minimum values of these parameters were found in rats born to females that were exposed to ethanol for three months. With the increase of ethanol exposure duration, lymph node numbers and their cross-sectional areas were increasing too. The largest numbers of lymph nodes was observed in rats born to females exposed to ethanol for four months, while the maximum cross-sectional areas was found in rats born to mothers after six month-long ethanol exposure.

Using electron microscopy, the reactive changes of epidermal cells in response to hypotonic conditions were studied in the representatives of three groups of marine invertebrates characterized by different levels of organization - Convoluta convoluta (Turbellaria, Acoela), Amphiporus lactifloreus (Nemertini) and Saccoglossus mereschkowskii (Enteropneusta). On the basis of functional resemblance of absorption and pinocytosis, the peculiarities of absorptive proximal tubule epithelium of human kidney under intensive protein transport were examined at the ultrastructural level. The resemblance of the epithelial tissue reactive changes in response to the damaging was demonstrated factors in invertebrates and in humans.

A comparative analysis of the basal level of the cytoplasmic calcium concentration in the intact intestinal isolated smooth muscle cells (SMC) of different phenotypes and the dynamic changes of its concentration in the SMC during the stimulation of their contraction, was performed. In this study, the SMC were isolated from the proximal colon, using collagenase dissociation. Confocal and fluorescence microscopy with the fluorescent probes Fura-2AM, to study the concentration of Ca2+ and MitoTracker Red, to study the activity of mitochondria, were used. It was found that the different phenotypes of visceral SMC, despite some differences in the basal levels of the cytoplasmic Ca2+ concentration, were characterized by the similar calcium response during the contraction stimulation, which indicates the identity of the mechanisms triggering contractile activity in different types of SMC.

This review contains the data on the representation of dopaminergic system in the amygdala and its functional importance in the realization of neuroendocrine functions of the amygdala as a reproductive center. The evidence presented indicate the combined participation of dopamine and sex steroids in the regulation of amygdala activity, which exerts a modulating influence both on the centers of gonadotropin secretion and release and on centers of sexual behavior in the hypothalamic area of the brain. It is shown that a significant role in this process belongs to the chemosensory information coming to amygdala from the olfactory bulbs, in which the functional activity of dopaminergic system is also controlled by the amount of sex steroids. This review also presents the data indicating the changes in dopamine metabolism in amygdala structures in the process of formation of the stress-response, food, maternal, aggressive-defensive and deviant behavior.