Reparative changes in the sensorimotor cortex of the offspring in moderate prenatal alcoholism]

Sensorimotor cortex of 21-, 30-, 60-day-old offspring given prenatally moderate alcohol (2 g/kg) manifested signs of compensatory type: double nerve and glial cells, open capillaries, nearby nerve and glial cell bodies with basal membrane of capillaries. Intracellular reparative processes in dystrophic neurons were observed: nuclear activation, hyperplasia of cytoplasmic organelles, hypertrophy of some of them. Reparative processes are more distinct in 30-day-old rat offspring In 60-day-old offspring a polymorphic pattern of cortical synapses ultrastructure was found. However, dystrophic changes of neurons and interneuronal connections still remain.     

Effect of alcoholic intoxication of female mice prior to pregnancy on the ultrastructure of neurons in the sensorimotor cortex of the progeny

Sensorimotor cortex in the offspring of female rats alcoholized in the prepregnancy period revealed signs of delayed neuronal development and dystrophic changes in the neurons especially on the 14th day after birth. In 21-day-old animals the reparative changes increased, but normalization of neuronal ultrastructure was not observed. The dystrophic changes suggest that prenatal brain hypoxia plays an important role in the pathogenesis of alcohol-induced neuronal lesions in the offspring.     

Postnatal physiological development of rats after acute prenatal hypoxia

The aim of study was to investigate the physiological development of the brain and behaviour in rats subjected to prenatal hypoxia on the 13.5th day of embryogenesis. We have found that such rats manifested a delayed physiological development and a change in nervous tissue of the sensorimotor cortex, as well a disturbed formation of motor responses during the first month of postnatal ontogenesis. During maturation these modifications were in part compensated, however we observed a decrease of the rats' ability to learn new forepaw movements. The destruction of the brain tissue and the modification of neurons composition in the sensorimotor cortex correlated with changes of behaviour at different stages of ontogenesis. Thus, changes of the conditions under which an organism develops during embryogenesis, predetermine a disturbance in ontogenesis and the learning ability.     

Effect of chronic alcoholic intoxication in the rat on the structural organization of the caudate nucleus in their progeny

By means of light (Nissl and Golgi), electron microscopy, as well as using morphometry, structure of neurons and interneuronal connections of the nucleus caudatus has been studied in 21-day-old rats reproduced by chronically alcoholized parents. As demonstrated the investigations, in young rats, physically underdeveloped, there are some signs of a delayed maturation in neurons, dendrites and synapses. Certain distrophic and reparative shifts are observed in all experimental animals. The distrophic changes of neural structures in the nucleus caudatus preponderate over the reparative ones, and in the destructive course not only the neuronal body is involved, but its processes, as well. The lesions of the latter influence organization of the synaptic contacts. This is demonstrated as a sharply decreased number of synapses of the formation studied in the field of vision. The occurring disturbance in the structure of dendrites, which play an important role in the primary integration of the information received by the neuron, can cause development of certain mental disorders in children born in alcoholic families. The reparative changes in neurons and interneuronal connections revealed suppose possible reversibility of the morphological changes observed in the offspring of drunkards.     

Some data on postnatal maturation of the cerebral cortex in cat

This paper describes the neurons in different cortical areas and traces their postnatal changes. Rapid Golgi and Golgi--Kopsch impregnation were carried out in 1-day-old and 9-day-old kittens. The maturation of the pyramidal neurons can be observed mainly on their basal dendritic orientation and on development of the dendritic spines. The differentiation of the interneurons (non-pyramidal) also proceeds on the first postnatal days. These, though slightly less mature than the associated pyramidal neurons, are identifiable already on the first postnatal day. It is concluded that there are significant differences in the maturation of the neurons in the various cortical areas.     

Establishment of the afferent function of the striatum in the rabbit during early ontogenesis

The study is dedicated to electrophysiological analysis of development of the caudate nucleus afferent function in rabbits in early postnatal ontogenesis. By amplitude-temporal parameters of the evoked potentials (EPs) of the caudate nucleus, recorded in response to stimulation of afferent inputs from the cortical regions (motor and limbic) and substantia nigra, similar dynamics of these afferent pathways functional maturation is revealed from the beginning of functioning (in the age of 3-5 days) to the definitive level (by the 30th day of life). The most significant changes of the amplitude-temporal parameters of the evoked potential, particularly of latencies are observed during the 3d week of postnatal life. On the basis of the obtained data, the conclusion is made on the formation of a common system of striatum sensory integration in the 3d-4th week of rabbits life. This age period is considered as critical.     

Ontogeny of the mouse motor cortex. The polymorph layer or layer VI. A Golgi and electronmicroscopical study

Summary The development of neurons and their synapses of the mouse motor cortex has been studied from the first postnatal day up to an age of three weeks both electronmicroscopically and with the Golgi method. Special attention has been paid to the maturation of the different cell types in the sixth cortical layer and their dendritic organization within this layer.The polymorph layer is subdivided into two zones: an internal (VIb) and an external one (VIa). In these zones six different cell types can be identified both electronmicroscopically and with the Golgi method: large, small and inverted pyramidal cells in VIa; horizontal cells, star cells and small pyramidal cells in VIb.Spines of apical dendrites of large pyramidal cells in sublayer VIa can be detected as early as the 6th postnatal day. About the ninth day the basal dendrites as well show emerging spines. Somatic spines are found only on the large pyramidal cells and disappear slowly towards the end of the 3rd postnatal week.The small pyramidal cells show developing spines on their apical dendrite in the first half of the second postnatal week. The final density and distribution of spines is reached by the stem dendrites towards the end of the second week, by the basal dendrites during the third week. The maturation process of the improperly orientated neurons occurs in time in between the large and the small pyramidal cells.The axo-somatic synapses appear in general at a later date than the axo-dendritic ones. In the horizontal cells axo-somatic synapses are visible already at the seventh postnatal day.At the end of the first week especially in layer VIb many immature neurons with an ovoid or round nucleus are present having little if any endoplasmic reticulum organised as ergastoplasm.Towards the end of the second week however most neurons in the polymorph layer have a well developed endoplasmic reticulum.Electronmicroscopical pictures reveal in outgrowing dendrites many enlargements filled with vesicles, these correspond to the varicosities seen in Golgi pictures. At nine days postnatally the first myelinated fibres appear.Aided by grant (R-209-67) from the United Cerebral Palsy Research and Educational Foundation, New York.     

Ultrastructural organization of the septum pellucidum in dogs subjected to long-term partial intraspecific isolation

The dogs have been kept under conditions of a partial intraspecific isolation for a long time, beginning from early stages of the postnatal ontogenesis. The reactive changes in neurons, interneuronal contacts are shown to produce proliferation of neuroglial cells and a number of their ultrastructural reorganizations. Phagocytic cells--astrocytes and microgliocytes--activate. However, enhancement of trophic processes is noted, manifesting itself as hyperplasia of lamellar processes of astrocytes in the neuropil, as an increased number of neurons with subsurface cisterns, in their area an astrocyte process is constantly revealed.     

Development of the caudate nucleus of rats in postnatal ontogenesis and formation of cholinergic mediation in it]

Morphological maturation of the rat's caudate nucleus and formation of cholinergic system in it were studied in postnatal ontogenesis. Under investigation were newborn rats, 7, 14, 21 day old rats and adult animals. The growth and maturation of the caudate nucleys were most intesne during the first two postnatal weeks, it was somewhat descreased by the beginning of the third week and continued in later terms as well. The structure of dendrites and axons became complicated during the first two weeks, the axo-dendritic contacts being also formed. The neuron structure in 14 days old rats was similar to that of adult animals. The activity of acetylcholinesterase in the caudate nucleus of 7 and 14 days rats was not great. It sharply increased by the 17th day and reached the level of adults with 3 weeks after birth. Possible correlations of the morpho-chemical maturation of the caudate nucleus and formation of motor activity in rats is discussed.     

Correlation of the destructive and reparative processes in neurons of the cerebral cortex in rats after thermal injury

Rat brain sensorimotor cortical neurons were investigated in thermal trauma, using electron microscopic radioautography. RNA synthesis and destructive neuronal changes (chromatolysis, nuclear and mitochondrial damage) have been determined. It has been established that the development of a reparative process--ribosomal RNA synthesis--was roughly parallel to the appearance of destructive changes and was marked in neurons with considerable ultrastructural disturbances.     

Morphometric and histochemical characteristics of the frog sartorius muscle in ontogeny]

Morphometric and histochemical investigation of musculus sartorius was performed in ontogenesis in Rana ridibunda and Rana temporaria. Muscular composition was characterized according to the type of muscular fibres. Spectrum of lactatdehydrogenase isoenzymes was studied at different developmental stages. As the studies demonstrated, musculus sartorius underwent some essential changes in ontogenesis which manifested themselves in increasing number of muscular fibres and their areas, in changing LDG isoenzymic spectrum. Differentiation of the muscular fibres three types takes place at the 30th stage after P. V. Terentiev and depends on the nerve system maturation.     

Neuronal Organization of Mammalian Stellate Ganglion in Postnatal Ontogenesis

The paper considers the problem of peculiarities of maturation of the stellate ganglion nerve elements in mammals of different species. This process differs in precocious and altricial animals. It has been shown that in spite of some individual peculiarities, the neurons, fibers, and conducting pathways in altricial animals are not, on the whole, completely formed morphologically and functionally. In the course of postnatal ontogenesis, not only an increase of cell sizes and development of dendrite tree, but also reorganization of nerve connections with target organ occur. The postnatal ontogenesis is also accompanied by an increase of the excitation transmission rate along the fibers and by their myelination. The asymmetry of the right and left stellate ganglia (SG) by their sizes and functional peculiarities, which exists in adult animals appears as soon as at early stages of postnatal development. The neural elements of precocious animals are changed to a lesser extent in postnatal ontogenesis and are, in many aspects, similar to those of adult organisms as early as at birth.     

Disturbances in Formation of the New and Old Cortex at Changes of Conditions of Embryonic Development

Using a model of acute hypoxia during pregnancy of rats, changes in the development of old (hippocampus) and new (sensorimotor) cortex associated with disturbance of neuronogenesis have been revealed in the studied brain structures at the period of action of a pathological factor. It was found that in rats submitted to hypoxia at the 13–14th days of embryogenesis, the number of degenerating neurons (including the pyramidal ones) at various levels of chromatolysis increased since the 5th day after birth; the increase was present for the entire first month of postnatal development. In the cortex of rat pups submitted to prenatal hypoxia there were observed deformation of neuronal bodies, vacuoles in the cytoplasm, shrinkage of apical dendrites of pyramidal neurons and delayed development of the structure (time of the appearance of spikes, formation of structural elements and the size of the cells) of the nervous tissue of the brain of the rat pups exposed to prenatal hypoxia. The columnar structure of the cortex was disturbed. In hippocampus, the process of degeneration of neurons started by 2–3 days later than in the cortex; by two weeks of postnatal development a massive degeneration and death of a part of neurons were also revealed. The morphometrical analysis showed a decrease in the number of neurons and their total area in the sensorimotor cortex (the layer V) and an increase in the number of glial elements at the 10–17th days after birth. In the hippocampus a decrease in the area occupied by neurons and in their size was detected in adult animals. The adult rats submitted to prenatal hypoxia were found to have disturbances of memory and learning. A correlation was shown between the disturbances of the conditions of embryonic development and the changes in the ability of learning and storage of new skills in the offspring.     

The development of thalamocortical connections studied by using carbocyanine dyes in the early ontogeny of rats]

We studied the differentiation of neurons and development of their connections in the occipital cortex and thalamic areas of the brain in early ontogenesis of rats: from day 11 of embryogenesis until day 19 of postnatal development. We used the method of staining of brain tissues by carbocyanine dyes after its preliminary fixation in aldehydes. Three carbocyanine dyes were used: DiI, DiO and DiA. We showed the dynamics of structural differentiation of the cortical neurons and lateral geniculate body of the thalamus and the specificity of formation of the axonal pathways between the neocortex and thalamic areas. The results obtained confirmed the hypothesis on ordered spatial-temporal growth of the cortical and thalamic fibers in early embryogenesis and revealed synchronous development of both classes of neurons of the lateral geniculate body. Retrograde and anterograde staining of the nerve cells processes by DiI and DiO showed fine morphological details of their structure. DiI provided for a good staining of the cells until day 19 of postnatal ontogenesis and DiO, until the end of embryogenesis, while DiA was not capable of diffusion in the fixed tissue.     

Protein synthesis in the critical periods of early postnatal ontogeny: its role in the development of the interspecific aggressive behavior of rats

Chronic administration of cycloheximide to young rats from 15-th to 30-th postnatal day before daily 3-hour seances of their contacts, disturbed the formation of animals intraspecies aggressivity. In adults it was manifested by hyperaggressivity and by changes of proportions of different reactions in the integral act of aggressive behaviour. By their character these disturbances were close to those observed in the young rats completely deprived of social contacts in this period of ontogenesis.     

Development of different types of muscle fiber in the postnatal ontogeny of guinea pigs

As demonstrates estimation of myosin ATPase and SDG activity, the guinea pig is already born with differentiated muscle fibers (MF), and the first histochemical differences between them take place in the uterine 10 days before birth. Tonic oxidative fibers of the first type, arranging hexagonally, develop especially quickly at early stages of postnatal ontogenesis. Their relative contents up to the end of the observations (185 days) do not change, and area of their transversal section increases but slightly in comparison to the phasic fibers. The main age changes of the muscle tissue are connected with formation and rearrangement of the phasic fibers. The most intensive reconstructions of the phasic fibers coincide with the period of game activity and sex maturation. In mixed muscles the part of the glycolytic fibers increase during the postnatal ontogenesis. In the process of ontogenesis the soleus muscle fully consists of oxidative fibers. The definitive level of the MF development is established after the guinea pigs have reached their sex maturation. Comparing the results of the given investigation with the previous data on development of MF in rats, it is possible to conclude that term and premature animals have various rates in development of the muscle system, however, main stages of myogenesis coincide, though they are connected with various phases of ontogenesis.     

Mathematical analysis of myelin structure of nerves of the brachial plexus in antenatal and early postnatal ontogenesis of man]

A gradual increase of the information entropy indices and a decrease of the excess percentage is observed in the course of antenatal and early postnatal ontogenesis of man. The indices of the information entropy reach their maximum and the excess percentage reaches its minimum in children younger than 3 years. At that time the myelinated fibres have the most various diameters. In the antenatal development of man the prevalence of fine (1--4 mkm) myelinated fibres makes the structure of the humeral plexus nerves more definite while in the postnatal ontogenesis their structure is less definite since the myelinated fibres of different diameter are met with almost the same probability.     

The postnatal development of the genital system in male rats following the prenatal administration of corticosterone

Corticosterone administration to pregnant Wistar rats on days 16 and 18 of pregnancy leads to changes in genital system of male offspring during postnatal ontogenesis: reduction of ano-genital distance in two days old rats, increase of preputial glands' weight in 35 and 70 day old embryos, changes in nature of puberal increase in testosterone blood level from day 35 to day 70 of life. The obtained data suggest that the increase in the corticosteroid level in blood of pregnant females owing to any stress factor can affect the postnatal development of genital system of male offspring.     

Disorders of the dynamics of postnatal development of monoamine oxidase activity in the brain as affected by the antenatal action of alcohol

The activity of different types of monoamine oxidase (MAO)-MAO, type A (substrate serotonin) and two types of mixed MAO forms using tyramine or dopamine as substrates, in different brain regions of the rat offspring exposed prenatally to ethanol was investigated on the 30th and 60th day postnatally. The present study has revealed differences in the development of brain MAO activity during ontogenesis. Disturbances in the activity of all MAO types investigated as well as the distortion of their postnatal development have been observed in the brain of the rat offspring exposed prenatally to ethanol. The possible teratogenic effect of ethanol on the developing fetal brain is discussed.     

Dendritic morphology and spine density is not altered in motor cortex and dentate granular cells in mice lacking the ganglioside biosynthetic gene B4galnt1 - A quantitative Golgi cox study

Gangliosides are characteristic plasma membrane constituents of vertebrate brain used as milestones of neuronal development. As neuronal morphology is a good indicator of neuronal differentiation, we analyzed how lack of the ganglioside biosynthetic gene Galgt1 whose product is critical for production of four major adult mammalian brain complex gangliosides (GM1, GD1a, GD1b and GT1b) affects neuronal maturation in vivo. To define maturation of cortical neurons in mice lacking B4galnt1 we performed a morphological analysis of Golgi-Cox impregnated pyramidal neurons in primary motor cortex and granular cells of dentate gyrus in 3, 21 and 150 days old B4galnt1-null and wild type mice. Quantitative analysis of basal dendritic tree on layer III pyramidal neurons in the motor cortex showed very immature dendritic picture in both mice at postnatal day 3. At postnatal day 21 both mice reached adult values in dendritic length, complexity and spine density. No quantitative differences were found between B4galnt1-null and wild type mice in pyramidal cells of motor cortex or granular cells of dentate gyrus at any examined age. In addition, the general structural and neuronal organization of all brain structures, qualitatively observed on Nissl and Golgi-Cox, were similar Our results demonstrate that neurons can develop normal dendritic complexity and length without presence of complex gangliosides in vivo. Therefore, behavioral differences observed in B4galnt1-null mice may be attributed to functional rather than morphological level of dendrites and spines of cortical pyramidal neurons.