[Formation of structural and ultrastructural organization of striatum rat postnatal ontogenesis upon changes in their embryonal development].

By light microscopy (by Nissl and Golgi), electron microscopy, and immunohistochemistry methods, formation of structure of the brain striatum dorsolateral part from birth to the 3-month age was studied in rats submitted to acute hypoxia at the period of embryogenesis. It has been established that hypoxia at the 13.5th day (E13.5) leads to a delay of neuronogenesis for the first two weeks of postnatal development as compared with control animals, while the majority of large neurons at this period are degenerated by the type of chromatolysis with swelling cell body and processes and lysis of cytoplasmic organoids. By the end of the 3rd week, shrunk hyperchromic or picnomorphic neurons with the electron-dense cytoplasm and enlarged tubules of endoplasmic reticulum and Golgi complex were also observed. An increased number of swollen processes of glial cells was detected in neuropil around degenerating neurons. By the 30th day as well as in adult rats there was observed destruction of mitochondrial apparatus, an increase of the number of lysosomes, and the appearance of bladed nuclei - signs of apoptotic cell death, which was also confirmed by an increased expression of proapoptotic p53 protein and its colocalization with caspase-3 in a part of neurons. Morphometrical analysis has shown a decrease of density of striatum cell arrangement and a change of ratio of different cell types in the rats submitted to hypoxia as compared with control group. At early stages of postnatal ontogenesis there was the greatest decrease (42.3% at the 5th day, 14.2% at the 10th day, p < 0.01) of the number of large neurons with the area more than 80 microm2. After 3 weeks of postnatal development the number of middlesize neurons (30-95 microm2) decreased (by 11.8-19.2%) as compared with control. The obtained data show that a change of conditions of embryogenesis (hypoxia) at the period of the most intensive proliferation of the forebrain neuroblasts leads to disturbances of the process of formation of the striatum nervous tissue. This can be the cause of delay of development and disturbances of behavior and learning observed in rats submitted to prenatal hypoxia.

[Formation of striatum structural and ultrastructural organization in the early postnatal ontogenesis of rats subjected to altered conditions of their embryonic development].

Formation of the structure of striatum during two postnatal weeks in rats subjected to acute hypoxia during various periods of their embryonic development was studied using light microscopic (Nissl's stain and Golgi's silver nitrate impregnation) methods and electron microscopy. This study was supplemented by a simultaneous investigation of physiological development of the same population of rats. The data obtained demonstrated that prenatal hypoxia on day 13.5 of embryonic development (E13.5) led to a delayed neurogenesis (retardation in the development of neuropil elements and cell differentiation) as well as to the malformation of the structure of striatum (degeneration, in particular, chromatolysis of neurons and glial nodule formation). Morphometric analysis demonstrated that prenatal hypoxia on E13.5 resulted in a statistically significant decrease in cell number in the striatum, these changes being especially pronounced in large neurons. Prenatal hypoxia on E18.5, however, caused no significant changes in striatum. Structural changes in the striatum were shown to be accompanied by significant changes in the physiological development of animals. The data obtained demonstrated that the alteration of the conditions of embryogenesis (hypoxia) during the period of most intensive proliferation of forebrain neuroblasts resulted in the disturbances of the formation of both striatum nervous tissue of the organism as a whole during early postnatal ontogenesis.

[The development of connections in the tecto-thalamo-telencephalic visual system of the brain in 13-day-old chick embryos]. / Razvitie sviazei v tekto-talamo-teléntsefal'noi zritel'noi sisteme mozga 13-sutochnykh kruinykh émbrionov.

Light and electron microscopic studies have been made on degenerative changes in the nervous tissue induced by experimental destruction of the median brain bulb at the 5th day of incubation, in parts of the tecto-thalamo-telencephalic visual system in 13-day chick embryos (in the visual tectum, round nucleus of the thalamus and ectostriatum of the telencephalon). It was shown that to this period tecto-thalamic connections are already formed in the visual system, whereas thalamo-telencephalic connections are, presumably, indirect ones.

[Tecto-thalamo-telencephalic visual system of the brain in 13-day-old chick embryos]. / Tekto-talamo-teléntsefal'naia zritel'naia sistema mozga 13-sutochnykh kurinykh émbrionov.

Light and electron microscopic studies have been made of the nervous tissue in three parts of the tecto-thalamo-telencephalic visual system--i.e. tectum opticum, nucleus rotundus of thalamus and ectostriatum of telencephalon--of 13-day chick embryos. Neuroblasts and neurones at various stages of differentiation were described together with various types of synaptic and nonsynaptic intercellular contacts in the neuropil of these brain structures. Heterochronous maturation of these parts of the visual system in embryogenesis was noted which reflects the level of their phylogenetic maturity. Being phylogenetically more ancient structures, tectum opticum and nucleus rotundus reveal differentiation earlier than ectostriatum which is phylogenetically younger.

[Comparative study of the structural organization of the 2 divisions of the hindbrain of 10-day-old chick embryos]. / Sravnitel'noe issledovanie strukturnoi organizatsii dvukh otdelov konechnogo mozga 10-sutochnykh kurinykh émbrionov.

Light and electron microscopic investigation has been made of the main structural components of the nervous tissue in two divisions of the telencephalon (the dorsal ventricular ridge and striatum) in 10-day chick embryos. Special attention was paid to the degree of maturation of cellular elements of the nervous tissue, the development of neuropil and the level of synaptogenesis. The data obtained suggest heterochronous maturation of the divisions investigated. Striatum, being phylogenetically more ancient structure, is formed prior to the dorsal ventricular ridge.

[Dynamics of the early ultrastructural changes in sensorimotor cortical neurons of the rat brain after exposure to high doses of gamma-neutron radiation]. / Dinamika rannikh izmenenii ul'trastruktury neironov sensomotornoi zony kory golovnogo mozga krys posle deistviia vysokikh doz gamma-neitronnogo izlucheniia.

At early times (15 min to 6 h) after whole-body gamma-neutron irradiation of mature rats with a dose of 10 Gy reactive changes occur in neurons of the sensimotor cerebral cortex which can be interpreted as a manifestation of the enhancement of functional and metabolic activity of nerve cells followed by inhibition thereof.

[Formation of the muscular and neural components of the femoral artery wall of the dog in early postnatal ontogeny (an ultrastructural and histochemical study)]. / Formirovanie myshechnogo i nervnogo komponentov stenki bedrennoi arterii u sobak v rannem postnatal'nom ontogeneze (ul'trastrukturnoe i gistokhimicheskoe issledovanie).

In puppies of various age (newborn, 2-week-old. 1- and 3-month-old) formation of smooth muscle and neural components in the femoral artery wall has been studied electron microscopically and histochemically. As demonstrate the electron microscopic data, the femoral artery wall is mainly formed by birth, nevertheless, structural components of its each tunic are at various stage of maturation and only by the 3d month the differentiation and specialization process of all cellular elements is fully completed. Owing to a combination of techniques used, it has been possible to follow the dynamics in formation of the innervation apparatus of the femoral artery. In the newborn animals the adrenergic apparatus of the femoral artery is presented mainly as thick fibers of a cable type; they form a plexus with loose loops at the periphery of the external tunic. Varicosities are scanty. By the 3d month there is a well developed network of the adrenergic fibers at the border of the middle and external vascular tunics. Some terminals penetrate into the muscular tunic. There is a great number of varicosities in the neural fiber axons. At the border of the middle and external tunics of the vessel, complex neuro-muscular interrelations are forming with an aim to bring functionally closer the main structural components of the wall. In the course of the early postnatal ontogenesis in dogs up to 3 months of age, in the femoral artery wall certain processes take place directed to ensure the neuroregulatory vasomotor properties of the vessel.

[Ultrastructure of the neural plexus of the wall of the anterior mesenteric artery in hens]. / Ul'trastruktura nervnogo spleteniia stenki perednei bryzheechnoi arterii u kur.

As it has been demonstrated in 10-day-old chickens by means of light and electron microscopy, the wall of the anterior mesenteric artery in hens has two well defined smooth muscle layers: longitudinal and circular. The innervation apparatus of this vessel wall consists of 3 plexuses (adventitial, muscular external and internal) which are parts of a single complex vascular plexus. All the neural fibres of this plexus are supposed to be adrenergic.

[Formation of the ultrastructure and adrenergic innervation of magistral vessel walls in chicken ontogenesis]. / Formirovanie ul'trastruktury i adrenergicheskoi innervatsii stenki magistral'nykh sosudov v ontogeneze kur.

Histochemical and electron microscopic investigation on dynamics of ultrastructure and adrenergic innervation formation in the wall of the femoral artery and vein, in the mesenteric artery and vein and in the aorta has been performed in 10-20-day-old chick embryos and in chickens during first days of life. In the course of embryogenesis, myoblasts of the media tunica have been demonstrated to transform into highly differentiated and strictly specialized smooth muscle cells. Simultaneously, neural fibres from the periphery of the vascular wall gradually penetrate up to the border of the external tunica and tunica media and varicosities with axoplasmic vesicles appear along their course. Owing to these two processes, by the time of hatching, the vascular wall has possessed a certain morphological substrate for the neural-muscular relations.

[Structure of the wall of thoracic lymphatic duct of dogs in postnatal ontogeny]. / Izuchenie stroeniia stenki grudnogo limfaticheskogo protoka u sobak v postnatal'nom ontogeneze.

Light and electronmicroscopic studies have been made on the structure of the wall of the thoracic lymph duct in puppies within 3 months of their postnatal life. It was shown that differentiation and specialization of the smooth muscle cells is accomplished in the main features to the 3rd month of postnatal life. Within this period, the number of the nervous fibers increases, and their linking to the media becomes more close. Absence of dense neuro-muscular contacts indicates distant pattern of the effect of neuromediators on the effector cells. The data obtained demonstrate that during postnatal ontogenesis of dogs changes take place in the barrier properties of the wall of the lymph duct, as well as the formation of morphological substrate for active contractile activity.

[Morphological study of the medial and posterior hypothalamus projections to the forebrain in turtles]. / Morfologichesko issledovanie proektsii srednego i zadnego gipotalamusa k perednemu u bolotnoi cherepakhi.

Ascending connections of the middle and posterior hypothalamic structures (n. ventromedialis, n. periventricularis arcuatus pars ventralis, n. mammillaris medialis) have been studied in the Emys orbicularis by means of anterograde degeneration and electron microscopic techniques. It has been demonstrated that the hippocampal cortex (its dorsomedial and dorsal parts) is the main cortical zone of projections for the nuclear formations mentioned above. Their projections are ipsilateral and occupy the external plexiform hippocampal layer. At the ultrastructural level, it has been demonstrated that axodendritic synaptic contacts in the dendrites with a middle-sized diameter make the major mass of the degenerating synaptic formations in the hippocampal cortex. At early postoperative stages (14 days), large axonal terminals are the main degenerating formations; the degeneration is of the "light" type. Degeneration of small and middle terminals begins later. On the 62d day the "dark" type degeneration is predominant. Besides the hippocampal cortex, the nuclear hypothalamic formations in question have projections into the subcortical structures: medial and lateral septal nuclei, paleostriatum and, to less degree--into the medial and cortical nuclei of the amygdala.

[External brain acetylcholinesterase in the ontogeny of precocial and altricial rodents]. / Vneshniaia atsetilkholinésteraza mozga v ontogeneze zrelo- i nezrelorozhdaiushchikhsia gryzunov.

The share of external acetylcholinesterase (AChE) has been determined in different brain structures of maturely and immaturely born rodents. It was found that in maturely born animals (guinea pigs) the share of external AChE in all the studied brain structures is the same in newborn and adult individuals. In immaturely born animals (albino rats) the share of external AChE to the moment of birth is significantly higher as that in adult organisms. During the development of the brain, the share of the external enzyme decreases, the decrease being more evident in the forebrain. It is suggested that this decrease is associated with fixation of the enzyme to the membrane, which is indicated in particular by the experiments with detergents.

[External acetylcholinesterase in different brain regions of a number of vertebrates]. / Vneshniaia atsetilkholinésteraza v razlichnykh otdelakh mozga v riadu pozvonochnykh.

In different parts of the brain (forebrain, midbrain, mesencephalon, nucleus caudatus, cerebellum and medula oblongata) parallel studies have been made on the total activity of AChE in homogenates and the activity of external AChE in slices. It was shown that the share of the external AChE in all brain structures decreases from Cyclostomes to Mammals. The most significant decrease was found in the forebrain. Within the same species (albino rats), phylogentically young brain structures (forebrain) contain smaller amounts of the external AChE, as compared to phylogenetically more ancient ones.

[Pulmonary capillary ultrastructure during accumulation of a phosphoorganic cholinesterase inhibitor in the lungs]. / Ul'trastruktura legochnykh kapilliarov pri nakoplenii v legkikh fosfororganicheskogo ingibitora kholinésteraza.

The ultrastructure of the blood-air barrier in rabbits was investigated during different periods after i. v. injection of high hydrophobic organophosphorus cholinesterase inhibitor GA-95. According to the biochemical data, this inhibitor is accumulated mostly in the lungs. The most pronounced changes observed 20 min after injection involved a significant increase in number of pinocytose vesicles in the cytoplasm of endothelial cells of lung capillaries. The morphological data may serve an indirect evidence for the inhibitor sorption at the surface of lung capillaries.