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—We studied the role of vascular endothelial growth factor (VEGF) in post-hypoxic damage of the rat brain and in the effect of saliphene, a GABA derivative that is considered as a potential neuroprotector. The method of quantitative immunohistochemistry was used to evaluate the expression of VEGF in the rat brain (neocortex and hippocampus) at the early and late periods after perinatal hypoxia and the subsequent administration of saliphene. Hypoxia resulted in an increase in the expression of vascular endothelial growth factor in the developing rat brain, and injections of saliphene prevented an increase in VEGF expression, leaving this index at the level of the control values. Thus, the changes the expression of vascular endothelial growth factor (VEGF) in the rat brain after perinatal hypoxia may be considered as a marker of the neuroprotective effect of saliphene.

We studied the effects of acute normobaric hypoxia on postnatal day 2 (model of preterm pregnancy) on reflex activity and behavior of juvenile male Wistar rats and the possibility of correction of behavioral deficit by administration of GABA derivative Salifen after hypoxia. It is shown, that perinatal hypoxia impaired righting reflex and forelimb grip strength and increased motor activity in juvenile male rats. Administration of Salifen for 14 days in a dose of 15 mg/kg improved reflex activity and behavior of rats, which indicates the prospect of further study of the therapeutic efficacy of this drug on models of neonatal encephalopathy.

Morphological characteristics of the elements of vessel walls in the microvasculature of rat neocortex were studied after perinatal hypoxia and subsequent introduction of salifen, a derivative of GABA, at long-term postnatal periods. It is shown that salifen at a therapeutic dose has a protective effect on the endothelium of blood vessels in the microvasculature of neocortex. It is found that after exposure to hypoxia followed by application of salifen no endothelial hypertrophy, appearance of numerous processes of endotheliocytes in the vascular lumen, and narrowing of the capillary lumen occur. The formation of la- mina densa is almost identical to that in the control. Swelling of perivascular astrocytes and reactive chan- ges of pericytes are also absent. In all layers of the neocortex the density of vessel distribution in the mic- rovasculature as well as their cross-sectional area in adult animals of the control group and after exposure to hypoxia and salifen application were approximately identical. It is shown that changes and restructu- ring of the capillary bed after exposure to hypoxia and application of salifen take place at earlier terms of development whereas by the maturity period stabilization of the structural parameters of the microvas- culature occurs. The protective effect of salifen on the elements of capillary walls determines the clinical effectiveness of its use and serves as a basis for further research in this direction.

The work was performed on Wistar rats, which were dividedinto 3 groups: 1st group--experimental rats subjected to hypoxia and treated with salifen (15 mg/kg for 14 days), 2nd group--control rats exposed to hypoxia only without treatment, and 3rdgroup--intact animals (8-10 animals in each group). Using themethods of light and electron microscopy, the effect of salifen onthe structural characteristics of the elements of the blood-brainbarrier (BBB) in the neocortex was studied in rats after exposureto hypoxia in the early postnatal period--on postnatal Day 2(model of human preterm pregnancy). The results showed thatsalifen had a positive effect on the state of the microvasculatureafter perinatal hypoxia, in particular, on the state of endothelialcells. Its active participation in the compensatory-adaptive reactions of the BBB in response to hypoxia exposure was detected,and the prospects of further studies of the protective properties ofsalifen are emphasized.

For the last time a particular interest of investigators has been attracted to the period of early newborn state when active process of adaptation of the organism to new life conditions occur defining its increased sensitivity to the effect of unfavorable environmental factors. An important place among these processes belongs to formation of homeostasis mechanisms and, primarily, the barrier mechanisms. The purpose of the present study was to investigate reactions of the hematoencephalic barrier (HEB) to action of perinatal normobaric hypoxia (a model of incomplete human pregnancy). Using light and electron microscopy, our investigation showed that after action of hypoxia all wall elements of neocortex capillaries revealed structural alterations which may cause impairment of microcirculation and increased permeability of HEB. It is established that differentiation of the basal membrane of a capillary wall takes place during the early perinatal period and the indicator of its differentiation is the formation of its plates - laminae rara et densa. After action of hypoxia, besides a delay of formation of the basal membrane, a vesicular type of its degeneration occurs. Key words: perinatal hypoxia, hematoencephalic barrier, capillary, endothelial cells, basal membrane.

In vitro and in vivo studies addressing the differentiation of neural stem and progenitor cells in the CNS require the use of highly specific markers for neurons and gliocytes. The aim of the present work was to study the distribution of a marker for differentiating neurons, i.e., doublecortin (DCX), in structures of the brain and spinal cord in rat embryos during the period preceding the formation of the cortical plate using immunocytochemical methods and light and confocal microscopy. DCX was detected in three types of cell in the developing nervous system at 13-14 days of embryogenesis: neurons giving reactions for the nuclear marker for differentiated nerve cells NeuN, migrating and differentiating neuroblasts, and some cells which are members of the population of radial gliocytes. The quite high selectivity of DCX expression allows use of this marker to be recommended for studies of the early stages of nervous system development in mammals.

Motor activity of rats was studied after experimental complete transection of the spinal cord at lower thoracic level. Treadmill training 1 day after the surgery was shown to lead to the appearance of movements in hindlimbs and restoration of the body weight support function. According to our data, the key moment in initiation of locomotor movements is stimulation of foot. Morphoimmunohistochemical investigation of the lumbar enlargement (study of proliferating cell nuclear protein, synaptophysin, and glial fibrillary acidic protein immunohistochemistry) revealed a rearrangement of motoneurons, interneurons, and the afferent chain in the distal part of the transected spinal cord. In the trained animals, there was observed the normal structure of motoneurons and the appearance of aggregates of the synaptophysin-immunoreactive structures lost after the surgery.

The topography of the lumbar enlargement of the spinal cord in rats was studied; an immunohistochemical method was used to determine the distribution of synaptophysin — a membrane protein of synaptic vesicles. Synaptophysin-immunoreactive structures were detected in the gray matter of all Rexed laminae, around most neurons and in the neuropil. Previously undescribed subpial synaptic contacts were detected immunohistochemically in the white matter and confirmed by electron microscopy. A non-myelinated component of the corticospinal tract, including axonal varicosities and synaptic contacts, was observed in the dorsal part of the white matter of the lumbar enlargement of the spinal cord.

Ectopic neurotransplantation can be used as an in vivo culture method for evaluation of the effect of various environmental factors (neurotransmitters, cytokines, and other bioactive substances) on histogenesis of the developing brain. The study was performed 1 day after allotransplantation of neocortical primordia from embryos of rats receiving intraperitoneal injection of p-chlorophenylalanine on day 11 of pregnancy. Under these experimental conditions the number of degenerating cells increased, while the count of mitotic neuroepithelial cells was 2.5-fold lower compared to neurotransplants of intact embryos at the same stage of development. Incubation of neocortical primordia in serotonin-containing medium before transplantation prevented cell death and promoted division of transplanted cells. Serotonin plays a role in the regulation of neuroepithelial cell proliferation and prevents cell death in the developing neocortex.

In this work we studied reactions of neural elements of various neocortex areas (sensomotor, visual, auditory) on action of acute normobaric hypoxia. The study is performed on the model of human premature pregnancy (action of normobaric hypoxia on rat pups at the 2nd postnatal day). There are revealed monotypical and monodirected structural reconstructions in all studied neocortex parts. The chosen parameters of hypoxic action initiate several direct reactions as early as at the next day: a decrease in sizes of cell bodies and in volume of the cytoplasm, as well as an enhancement, as compared with control, of the apoptotic cell death. By the end of the neonatal period (5 days), several ultrastructural alterations indicating deceleration of processes of differentiation of nerve cells are revealed: arrest of processes of complication of smooth and rough endoplasmic reticulum and of Golgi apparatus, a small number of single ribosomes and polysomes in the cytoplasm, a decrease of the number of growth cones of axons and dendrites in neuropil, delay and disturbance of myelination processes in nerve fibers. The detected morphofunctional reconstructions can serve the structural ground for development of neonatal encephalopathies.

Structural and cytochemical organization of the basement membrane (BM) of the developing human brain at the embryonic period of prenatal ontogenesis was studied using light and electron microscopy and immunocytochemistry. Ultrastructural study has shown that the basement membranes of capillaries growing into the brain anlage are at the stage of formation (from the complete absence to the stage of broken membrane, without characteristic differentiation into layers). At the same time, BM of the brain surface looks sufficiently differentiated and prevents contacts of cells of the developing brain with meningocytes. These data are in contrast with results of immunocytochemical study, which show that the basement membranes (according to reactions for fibronectin, laminin, and type IV collagen) are clearly contoured around growing capillaries and, hence, exist from the very beginning of the intracerebral angiogenesis. The explanation of the established discrepancy between electron microscopic and cytochemical data seems to be searched for in spatial distribution and organization of BM components.

Studies of the structural-functional organization of the boundaries separating different media in the CNS are needed for identification of the barrier mechanisms allowing the creation and maintenance of the constant-composition internal medium. The outer surface of the brain occupies a special position among the anatomical zones of brain barriers. In all areas, this is formed by layer I of the cortex, which serves as the collector of afferent fibers of cortical and extracortical origin and therefore has a key role in forming neocortical cytoarchitectonics at the early stages of ontogenesis [9, 13]. Some authors have suggested that there is a complex structure between the brain and the meningeal vessels, this being typical of the blood-brain barrier (BBB) [12], while other investigators believe that the typical CSFbrain barrier (CBB) occurs at this location, with all the corresponding structural elements [8]. Current data on the existence of a volume transmission effect and the role of barrier structures in forming and regulating the composition of the intercellular medium of the brain [4, 6] indicate that studies of the structural-functional characteristics of cellular and non-cellular elements on the brain surface as a boundary separating media are relevant. This could be significantly facilitated by use of the ontogenetic approach, allowing the development and differentiation of nerve and glial elements to be followed and compared in relation to the type of nutrition of nerve tissue, formation of the vascular bed, and the brain’s acquisition of definitive structural features. Increases in the organizational complexity of the brain in a series of vertebrates are paralleled by specialization and differentiation of its barrier systems [10]. Thus, there is significant interest in studying the organization of the surface barrier system of the human brain, data on the structure and formation of which are incomplete and contradictory. Thus, the aim of the present work was to study barrier structures on the outer surface of the forming human brain during the early prenatal period of development.

The method of ectopic transplantation of embryonic CNS rudiments makes it possible to study the mechanisms underlying adaptation of the transplanted embryonic rudiments. The production of nitric oxide by cells is considered as one of such mechanisms. NADPH-diaphorase is an index of the presence of nitric oxide synthase in cells. It was shown that the nerve cells of rat embryonic spinal cord transplants preserved their capacity to express NADPH-diaphorase after transplantation in the sciatic nerve of an adult animal for six months. The dynamics of NADPH-diaphorase-positive neurons of rat embryonic spinal cord developing after transplantation and in situ were studied. In spinal cord neck region, small bipolar NADPH-diaphorase-positive neurons were visualized on day 17 of prenatal development. After transplantation of the embryonic (day 15) spinal cord in the nerve, NADPH-diaphorase-positive neurons were formed later than in situ: within seven days. The results of histochemical studies carried out within six months after the operation suggest a protective role of NADPH-diaphorase in the neurons of allotransplants developing under the conditions of altered microenvironment and insufficient innervation and also suggest that nitric oxide can cause the death of neurons in long surviving transplants.

The reactions of forming synapses in rat neocortex to the effect of hypoxia in the early postnatal period (day 2) were studied. Using immunocytochemistry for synaptophysin demonstratoion and electron microscopic methods, the sensorimotor cortex was studied in rats at days 3, 4 and 10 of postnatal development (6 to 10 animals of each age) in both experimental and control groups (intact animals). Immunocytochemical study of the control animals demonstrated significant differences in the quantitative distribution of synaptophysin-positive structures in the different layers of the neocortex in the early postnatal period of development (day 5). It is shown that after exposure to perinatal hypoxia, more than 2-fold decrease of the optical density of the immunocytochemical reaction product took place together with the reduction of synaptophysin-positive granules distribution density in all cortical layers of. At the same time, electron-dense terminals demonstrating early degenerative processes were found. In the neuropil of the neocortex, a sharp decline in the number of growth cones, small processes and forming synapses was accompanied by significant changes of the electron density of synaptic, especially post-synaptic, membranes and densities. In the experimental animals, the number of growth cones and emerging synaptic structures were shown to increase only by postnatal day 10. Thus, the effects of hypoxia in the early postnatal period, causing disturbances of synaptogenesis, persist throughout the whole neonatal period examined.

Using light and electron microscopy and immunocytochemistry methods, structural organization of the formed blood-cerebrospinal fluid barrier (BCSFB) of the human brain choroid plexus in embryos of 6–9 weeks of development was studied. The main structures peculiar to the mature BCSFB have been established to appear with formation of the choroid plexus at the end of the 2nd month of the human intrauterine development. Fenestrae in the choroid plexus capillary endothelium are revealed since the 9th week of prenatal development. Characteristic of the human embryonic BCSFB are a poor development of the plexus capillary basal membrane, scanty pericytes, a high activity of interstitial macrophages, which suggests the barrier immaturity. A significant amount of cytoplasmic glycogen inclusions revealed in plexus epitheliocytes seems to be due to peculiar trophic requirements of developing brain cells under conditions of an insufficient development of the local blood supply.

Neurons of rat neocortex and spinal cord express NADPH-diaphorase after heterotopic allotransplantation into the sciatic nerve. These peculiarity of diaphorase expression in transplanted cells in comparison with brain cells developing in situ suggest an important role of afferent and efferent relationships in the development of NO mechanisms in neurons.

The present study was performed to develop a simple and reliable method for the combined staining of specimens to allow the advantages of immunocytochemical detection of astrocytes and assessment of the functional state of neurons by the Nissl method to be assessed simultaneously. The protocol suggested for processing paraffin sections allows preservation of tissue structure at high quality and allows the selective identification of astrocytes with counterstaining of neurons by the Nissl method. The protocol can be used without modification for processing brain specimens from humans and various mammals--except mice and rabbits.

The dynamics of reactive changes of a population density of microglial cells and the reversibility of their phenotypic forms were studied in the brain of neonatal rats at different time intervals after 1 hr-long exposure to acute normobaric hypoxia in the pressure chamber at the second postnatal day. Different areas of the neocortex (frontal, motor, somatosensory and visual) and of the hippocampus (CAI, CA3, CA4 and fascia dentata) were examined 1 hr, 3 hrs, 1 and 5 days after exposure to hypoxia. Microglial cells were demonstrated using an immunocytochemical staining with the monoclonal antibodies against Iba- 1 antigen. The results have shown that the reaction of microglia to acute hypoxia in both the neocortex and the hippocampus of the new-borns developed simultaneously and synchronously with the augmentation of cell death. The increase of a population density of amoeboid form of microglial cells in the brain areas studied was recorded already after 1 hour as a result of their migration from the subventricular region and the areas adjacent to large vessels from where they practically disappeared. The number of amoeboid microglial cells in this area has recovered rather quickly (in 3 hrs). The population densify of microglial cells, especially of amoeboid forms, sharply increased with the augmentation of cell death and remained unchanged for about 5 days.

The purpose of the present study was to examine the synaptogenesis in the dorsal raphe nucleus (DRN) in Wistar rats (n = 8-10 for each time point) in the end of prenatal (days 19 and 20) and early postnatal (days 5 and 20) periods, and to determine the role of serotonin in the formation of synaptic contacts during this period of development. It is shown that at prenatal dayl9 neuropil started to develop in DRN -d, DRN -v and DRN -1 in control (intact) animals, while the synaptic contacts appeared on cell processes. At prenatal day20 synaptic contacts were detected for the first time on neuronal cell body surface. The density of synaptophysin-positive granules on both the cell processes in the neuropil, and neuronal cell bodies was sharply and considerably increased by postnatal day 5. Subsequently, until postnatal day 20, the augmentation of their density was insignificant. Serotonin deficiency in a second half of prenatal development, induced by a single injection of parachlorophenylalanine to female rats at gestational day 16 resulted in a significant delay of synaptogenesis in DRN of their offspring in both prenatal and early postnatal periods. With the increase of postnatal age the density synaptic contacts was unequally augmented in various parts of DRN: in DNR-d it approached the control level, while in DRN-v and DRN-1 it remained significantly reduced. The results received suggest serotonin participation in synaptogenesis in DRN.

The formation of trigeminal motor nucleus (TMN) was studied in the early postnatal period in 21 female Wistar rats which received the serotonin biosynthesis inhibitor para-chloro-phenylalanine at prenatal Day 16 (the period of serotoninergic system formation). It was shown that the serotonin deficit during the prenatal period in rats resulted in the changes of TMN structural organization. In the early postnatal period, the delay of neuropil development, the reduction of cell body size with the partial loss of Nissl substance in some of the neurons, the presence of degenerating neurons with the signs of hyperchromatosis in all the parts of the nucleus, especially in TMN ventromedial part, were detected. At later stages, the destruction of motoneurons became slower, though some of them had morphological abnormalities. With the increase of the postnatal age (by Day 20) the number of motor neurons decreased, apparently, as a result of the gradual intensification of cell death. Simultaneously with the motor neuron degeneration in TMN parts studied, the astrocytic gliosis was observed.

The aim of the study was to evaluate, by using immunohistochemistry (demonstration of Iba-1 protein), the morphological features of the rat hippocampal microglia and to describe its cellular types during the response to a single total brain ischemia of 12 min duration. The results obtained suggest the existence of several morphologic types of microgliocytes in the intact hippocampus, while some more types appear in response to ischemic lesion of neurons. These changes in general population of the hippocampal microgliocytes is related to their functional activation. During the post-ischemic period (3, 7 and 14 days following the challenge), there appeared multiple micro-outgrowths of the microglial cell processes, which suggests the enhancement of their interaction with surrounding cellular elements and may be the manifestation of the process of the elimination of neuropil lesioned synaptic structures.

The study has shown the acute hypoxia in newborn rat pups to lead to disturbances of processes of formation of brain structures, behavior reactions, and learning in the subsequent ontogenesis. The single normobaric hypoxia at the 2nd day of life causes retardation of such integrative parameter or genera development and growth as body mass at the period of feeding. In such animals, essential disturbances of the sensorimotor development were revealed in forms of delay of reflex reactions of turning on a plane, negative geotaxis, and avoidance of edge. Also detected was action of hypoxia on hanging on a rope by using front legs (a symptom of muscle weakness). Morphological study has shown stereotypic reaction to the early postnatal action of hypoxia in all studies of all studied functional zones of neocortex - motor, sensomotor, auditory, visual. The death of nerve cells is predominant in the II-III associative layers, the sizes and number of pyramidal neurons are sharply decreased. Different hippocampus fields maturing in mammals show a characteristic response to hypoxia. In individual hippocampus fields there was detected different degree of death of neurons, predominant in the CA3 and CA4 fields. A possibility of modeling of perinatal encephalopathy with minimal brain dysfunctions in children is discussed.

The study has shown that influence of acute hypoxia in perinatal period leads to structural changes in motor and visual of the neocortex for 20 postnatal days in the form of disturbance of the structural organisation of the neocortex layers. Different fields of hippocampus in perinatal period differently react to hypoxia, and evidence of existence of a long-term perinatal hypoxia was obtained. It is established that after action of acute hypoxia in all the fields there is a cellular destruction, and thinning of pyramidal neurones layers. The most expressed cellular destruction takes place in fields CA4 and CA3. In process of augmentation, the destruction of cells remains appreciable in the field CA4, reduced in the field CA3 and not found in the field CA1; however, in fascia dentate, the destruction of granular neurones with age augmentation increases. Along with in reduction of the dimensions of cellular bodies pyramidal neurones in all fields of hippocampus takes place. Also in all fields of hippocampus, activation of astrocytic reaction occurs, more expressed in the field CA4. The hypoxia influence in the early postnatal period can affect synaptogenes, particularly the formation of giant synapses in a dentate fascia. Study of functional features of the excitatory system of such animals has shown that hypoxia can induce appreciable disturbances of behavioural responses. In rats, disturbances of inhibiting functions of the cerebral cortex, raised anxiety, and spatial learning and working memory disturbances have been noted.

The aim of this study was to determine the long-term effects of acute normobaric hypoxia in the perinatal period on the development of a hippocampal formation in rats. The experiments performed have shown that the exposure to hypoxia on postnatal day 2 resulted in a significant damage to the hippocampal field structure. Differential field sensitivity to the damaging factor was also detected. At postnatal day 20, the cell death was found in all the fields and the thinning of pyramidal neuron layers was observed. The neuronal death was mostly expressed in CA4 and CA3 fields. At postnatal day 30, the neuronal death remained significant in CA4 field, while it was reduced in CA3 field and was not found in CA1 field, however, in fascia dentata the death of neurons of the granular layers was increased. Along with it, the dimensions of the pyramidal neuron cell bodies were reduced in all the hippocampal fields. Also, in all the hippocampal fields, the activation of astrocytic reaction was found, which was more expressed in CA4 field, where gliosis was found to remain until prepuberal age (day 30).

The reaction of rejection takes place in most cases of xeno-transplantations. It can be suppressed by hydrocortisone which inhibits processes of cell immunity. As a result the take of transplants is observed in 100% of cases. Processes of proliferation and differentiation of their cell elements are delayed. Little differentiated cells capable of mitotic division were noted to group into rosettes which might result from trauma of embryonic nervous tissues during taking the material or a reaction to the action of the environment. The injury of the spinal cord is followed by the formation of a scar deforming the surrounding structures which is formed not only by the glial but also by the connective tissue cells of spinal membranes. Against the background of immunosuppression a small soft scar is formed between the transplant and the host spinal cord consisting mainly of fibrous astrocytes.

Experiments were carried out on the 19-day old rat embryos, the 5- and 45-day old rat pups, and the 1.4-1.5-year old rats. Phospholipids and their fatty acid composition in brain cell nuclei were studied using methods of extraction, two-dimensional thin-layer chromatography, and spectrofluorimetry. In the course of ontogenesis, the percentage of different classes of nuclear phospholipids was changed; at the postembryonic period, the unsaturation index of lipids (phosphatidylcholine and phosphatidylethanolamine) and the content of unsaturated (especially polyenic) fatty acids decreased. Microviscosity of nuclear membranes increased; this changes were also shown earlier in phylogenesis of vertebrates. Thus, the facts revealed in the present work correspond to the recapitulation law. It is suggested that such change of lipid ratio and of composition of their fatty acids as well as of the membrane microviscosity serve for regulation of functions of membrane proteins and have adaptive character.

Changes of expression of contractile proteins (alpha-actin and myosin of smooth muscle cell) and of collagen of IV type in stroma of human placental villi were studied at the diagnosed placental insufficiency (PI) in III trimester of pregnancy. The study revealed pronounced disturbances of expression of contractile proteins and collagen of IV type at PI. It is shown that in perivascular envelopes of vessels of stem and intermediate villi there is present a much greater amount of cells expressing smooth muscle actin and myosin. These cells are arranged by the denser concentric layers and more compactly than in norm and fill the intervascular space inside the villi. The width of perivascular envelopes of vessels is higher, while vascular lumens are lower than in norm. In terminal villi the capillary walls are thickened and the number of pericytes immunopositive against the smooth muscle cell alpha-actin and myosin as well as collagen of IV type is increased. The change of synthesis of the cytoskeletal contractile proteins and collagen of IV type is shown to lead to structural disturbances of villi of different types and of perivascular areas and vessels, which doubtlessly indicates their participation in pathogenesis of placental dysfunction and of disturbance of placental hemodynamics.

Study of born placentas with chronic functional failure established in the III pregnancy trimester has revealed several characteristic structural alterations of placentar villi and of its vascular bed elements. There has been shown a decrease of the number of terminal villi and an increase of their sizes (approximately 3 times) as compared with norm, a change of transformation of cytotrophoblast into syncytiotrophoblast, thickening of vascular endothelium, a decrease of the number of capillaries-sinusoids, and a decrease of the number of syncytiocapillary membranes, which leads to deterioration of conditions of the maternal-fetal diffuse exchange. It has been established that in placentar failure, expression of the vascular endothelial growth factor (VEGF) by cytotrophoblast cells, syncytiotrophoblast, and Kashchenko-Hoffbauer cells is enhanced as compared with norm, which can be considered a reaction to a decrease of intensity of placentar blood circulation.

It was found that intracerebral blood vessels in human embryo telencephalon first appear on the 7th week of prenatal development as capillaries with poorly differentiated walls and signs of functional immaturity. The formation of the basal capillary membrane consisting of laminin and type IV collagen starts immediately after the formation of primary capillary network.

The goal of the present work was to study composition and spatial-temporal distribution of cells containing various proteins of intermediate filaments (nestin, vimentin, GFAP) in various brain parts at the early postnatal period of rat ontogenesis. By using methods of immunochemical determination of proteins of intermediate filaments it has been established that at they early period of ontogenesis, in the course of maturation of the nervous tissue, in cells of cortex, hippocampus, and subventricular area there occurs a change ofimmunochemical profile of intermediate filaments: the nestin+/vimentin+/GFAP- -cells become the nestin-/vimentin-/GFAP- ones.

Motor activity of rats has been studied after complete experimental section of spinal cord at the lower thoracic level. A treadbun training performed one day after the operation has been shown to lead to the appearance of movement of hindlimbs and to restoration of function of support of the body weight. In our opinion, the key moment in initiation of locomotor movements is stimulation of foot. Morphoimmunohistochemical study (detection of nuclear protein of proliferation cells, synaptophysin, and glial fibrillary acid protein) of the lumbar enlargement has allowed revealing reorganization of motoneurons, interneurons, and afferent chain in the distal part of the sectioned spinal cord. In trained animals there are observed the normal structure of motoneurons and the appearance of aggregates of synaptophysin-immunoreactive structures lost after the operation.

human embryos, containing an anlage of the neocortex can be used as the initial material for transplantation [3, 4]. It has been placed into the cerebral cortex of adult rats, and the taking of the graft has been observed [5]. The time course of the proliferative processes and the differentiation of the cellular elements have been studied in this model, and it has been demonslrated that the prolonged existence, for six months and longer, of the trap. splant without signs of a cellular immune reaction is possible in a number of instances. The purpose of the present investigation was the elucidation of the characteristics of the development of a transplant of human embryonal nervous tissue in the rat spinal cord. Taking the great potentials for growth of segments of the telencephalic vesicles of human embryos, and data regarding the fact that they take well in homografts of the spinal cord of mammals [3, 4, 8, 7], into account, this division of the embryonal brain was specifically selected as the initial material for transplantation. Material and Methods. The investigation was carried out on 68 adult Wistar rats, weighing 200-250 g. Laminectomy of the VI thoracic vertebra was carried out in the animals under anesthesia (Calypsol in a dose of 200 mg/kg in combination with the inhalation of ether vapors). With monitoring by means of an operative microscope, the dura mater was opened, and a segment of donor brain measuring 2 mm 3 was introduced by a means of a glass cannula with an internal diameter of 0.5 mm into the spinal cord. Segments of the wall of the telencephalic vesicle of human embryos at the 8-10 week period of development, obtained after artificial interruption of pregnancy, were transplanted. The initial material for the transplantation was kept for several hours in Hanks' solution at t ~ = 4~ After the operation the animals were maintained in the usual vivarium conditions. Morphological investigation using light and electron microscopic methods was carried out 2, 3, 4, 8, and 12 weeks later. For light microscopy the material was fixed in Bouin's fluid. Paraffin sections, 5-7 Inn were stained with hematoxylin-eosin and toluidine blue after Nissl. For the electron microscopy, fixation of the brain was carried Out by perfusion of a 2.5% solution of glutaraldehyde in a 0.01 M phosphate buffer at pH 7.3-7.4, with subsequent treatment with a 2% solution of OsO4 in a 0.05 M cacodylate buffer, The material dehydrated in a series of alcohols of increasing concentration and in propylene oxide, and mounted in Epon. After the semithin sections were studied, collimated trimming of the blocks was carried out. The ultrathin sections, 50 nm in thickness, were obtained on an LKB ultratome, and studied under a JEM 100-B electron microscope. Results and Discussion. The wall of the telencephalic vesicle of the donor embryo at the 8-10 week period of development consists of cells of various degrees of maturity. Undifferentiated neuroepithelial cells, capable of mitotic division, are located in the ventricular zone. They are the forerunners of both nerve and glial cells. These cells, which are capable of migration, have an elongated form when stained with hematoxylin-eosin. A large number of mitotically dividing cells are observed particularly in the ventricular zone. The anlage of the ncocortex, the primary gray matter of the cortex, properly appears in embryogenesis from the eighth week of intrauterine development as a result of the migration of cells from the ventricular zone [1, 6]. It consists of cells of a high degree of maturity. As the formation of the primary gray matter of the cortex and the increase in the number of cells

The studies of CNS neural stem and progenitor cell differentiation both in vitro and in vivo, require the application of highly specific markers of neural and glial cells. The aim of the present investigation was to study the distribution of differentiating neuron marker doublecortin (DCX) expression in different structures of embryonic rat brain and spinal cord before cortical plate formation, using immunocytochemical methods, light and confocal microscopy. The presence of DCX was demonstrated in three types of cells of the developing central nervous system at days 13-14 of embryonic development: neurons which demonstrate positive reaction for nuclear marker of differentiated neural cells NeuN; migrating and maturing neuroblasts; some cells belonging to radial glial cell population. Sufficiently high selectivity of DCX expression allows recommending of its usage in the mammalian CNS early development investigations.

The aim of this study was to analyze the response of cyto- and syncytiotrophoblast elements of fetal part of allantoic placenta to general acute hypoxia and to determine their morphologic characteristics, which provide the basis for structural changes in placenta and for the disturbances in placental blood flow. Female Wistar rats on day 16 of gestation were exposed to hypoxia (8% oxygen concentration in the gas mixture) for 1 hr. Placenta was studied 1 and 3 days later. Short-term acute hypoxia during pregnancy was shown to induce an impairment of formation and maturation of the fetal part of placenta. In the labyrinth zone, apoptosis was enhanced and a significant number of hyperchromatic nuclei appeared in cyto- and syncytiotrophoblast, which lead to the loss of some cells of cytotrophoblast and resulted in the retardation of its development and transformation into syncytiotrophoblast. One day following hypoxia, a stimulation of adaptive processes was evident as demonstrated by a dramatic rise of mitotic activity in the cytotrophoblast of the labyrinth zone of placental fetal part. However, a delay of the labyrinth zone development persisted till the end of pregnancy. Number and volume of fetal blood vessels were decreased as compared to those in control. A sharp decline of number and size of sinusoids containing maternal blood as well as a significant decrease of blood volume in the sinusoids, suggest a spasm of the uterine and placental vessels causing an impairment of utero-placental blood circulation and development of placental insufficiency.

The aim of this investigation was to study the distribution of bcl-2 antiapoptotic protein in various structures of human placenta using immunocytochemical methods. Syncytiotrophoblast was found to have the greatest bcl-2 immunoreactivity, while cytotrophoblastic elements, connective tissue cells of the villi and the blood vessel walls were bcl-2-negative. It is suggested that accumulation of bcl-2 in the syncytiotrophoblast may reflect its high resistance to detrimental factors.

A comparative study has been performed of dynamics of development of ectopic transplants of embryonal (E14) neocortex anlages obtained from intact rats and from the rats administered with serotonin inhibitor para-chlorophenylalanine (PCPA) at the 11th day of pregnancy as well as after incubation of such anlages in the serotonin-containing medium. The goal of this work was to elucidate effect of serotonin on division and differentiation of embryonal neocortex cells. Study of degeneration, mitotic activity, and differentiation (by using immunohistochemical detection of nerve cell nuclear protein--NeuN) of transplanted cells has allowed establishing that serotonin promotes survival and differentiation of transplant neuroepithelial cells as well as participates in regulation of their proliferation. It is suggested that serotonin produces stimulation effect on the cell cycle rate of transplantated cells to thereby accelerate neuronal differentiation.

We compared the dynamics of the development of ectopic transplants of embryonic (day 14) primordial neocortex from rats injected with serotonin inhibitor (para-chlorophenylalanine; 400 mg/kg) on day 11 of pregnancy and transplants of similar primordial neocortex incubated before transplantation in a medium with serotonin (3 microg/ml). The study of mitotic activity and differentiation of transplanted cells showed that serotonin promoted survival of the transplanted neuroepithelial cells and their differentiation into nerve cells, and is involved in the regulation of their proliferation. We hypothesized that serotonin accelerated the cell cycle of transplanted cells, thus accelerating the neuron differentiation.

The goal of this work was to study changes structural and cytochemical organization of rat hippocampus activated astrocytes after a brief total brain ischemia. By methods of immunocytochemical determination of proteins of intermediate filaments, in was established that 7 days after the ischemia the functional activation of dorsal hippocampus astrocytes is morphologically manifested both as changes of size and shape of the cells and their processes and as accumulation of the intermediate filament proteins -GFAP and nestin. Two populations of the activated astrocytes are formed - more dispersed GFAP-positive astrocytes and nestin-positive astrocytes located predominantly in the area of massive death of nerve cells. The obtained data allow suggesting that the postischemic activation of astrocytes is accompanied by their acquistition of properties characteristic of immature cells of the nervous tissue; however, the absence of morphological signs of dedifferentiation does not permit these cells to be considered responsible for reparational neurogenesis in hippocampus.

The aim of the present study was to demonstrate a neuronal form of NO-synthase (type I NOS) in rat brain using immunocytochemical technique in comparison with the histochemical reaction demonstrating NADPH-diaphorase activity, as well as finding of optimal fixation protocol for the NOS demonstration. The histochemical reaction product was found to have strict cytoplasmic distribution. Immunocytochemical visualization of nNOS revealed not only cytoplasmic, but also nuclear localization of nNOS in some part of neural and glial cells without cytoplasmic nNOS staining. Searching for an optimal protocol of the material fixation and the primary antibody dilution, we succeeded in diminishing the intensity of intranuclear nNOS-like reaction while the specific cytoplasmic nNOS reaction was retained. The results obtained show that the optimal demonstration of nNOS in paraffin sections requires immersion fixation in Carnoy solution or posfixation in this solution following a perfusion with 4% paraformaldehyde solution.

Effect of serotonin (5-HT) deficit produced by administration ofp-chlorophenylalanine at a dose of 400 mg/kg to pregnant female mice on the day 8 of gestation and on the subsequent behavior of their offspring (hybrids F1 (C57BL/CBA)) was studied. The 5-HT deficit in prenatal ontogenesis leads to the following changes of behavior: 1) females and males of the experimental group show a higher level of the explorative activity in the "open field" than control animals; 2) in females of the experimental group at the age of 90 days, unlike control females and males of experimental and control groups, the explorative activity is extinguished at the threefold testing in the "open field"; 3) females of the experimental group have a decreased level of anxiety in tests "elevated plus-maze" and the "dark-light chamber". Males of the experimental group, on the contrary, have an elevated level of anxiety. The obtained data show that the 5-HT deficit at the prenatal period affects various aspects of behavior. The degree of the changes produced by the prenatal 5-HT deficit can have different manifestation depending on sex of the animals.