Morphofunctional characteristics of the pancreas in the progeny from females with experimental hypothyroidism]

Histophysiological pancreatic indices were studied in 1-, 21- and 30-day-old offsprings of white non-lineal female rats that were given antithyreoid drug mercasolil in the dose 3 mg/kg of body weight during pregnancy and lactation. Chemical inhibition of maternal thyreoid function results in decreasing weight index of the offspring's pancreas, in decreasing section area of the terminal secretory parts, in narrowing the homogenous zone of exocrine pancreocytes, in decreasing the portion occupied by the endocrine part on the section area, as well as in decreasing the index of B/A cells ratio of pancreatic islands and of nuclear volume of basophilic insulocytes. It is possible to conclude from the data obtained that maternal hypothyreosis produced by mercasolil unfavourably affects the process of structural and functional setting and the status of the pancreas in the offspring.     

Morphofunctional characteristics of the adrenal glands in the progeny from females with experimental hypothyroidism]

Under study were the morphofunctional features of adrenal glands of 1, 10, 20, 30 and 40-day-old rats born by females with experimental hypothyrosis obtained by bilateral subtotal parathyroidectomy and blocade of the gland functioning by mercazolil (3 mkg/kg). The experimental treatment preceded pregnancy. The antithyroid drug was injected during pregnancy and lactation. The posterity of experimental animals was established to have a decreased need in oxygen as compared with controls. Their adrenal glands were of less weight (especially in off-springs of parathryodidectomized rats in the neonatal period). There are a number of morphometrical and histochemical signs suggesting the suppression of the functioning of the cortical and medullary substance, including the period of adaptation of the organism to the extrauterine life.     

Changes in oxygen tension in the cerebral cortex during hemodilution

Wistar rats were subjected to gradual blood replacement with 7% albumin (hemodilution). Hematocrit and mean arterial pressure were measured periodically. Polarographic platinum microelectrodes with a tip 3-8 microns in diameter were used to study variation of oxygen tension (pO2) in the brain cortex during hemodilution. Some areas showed a significant decrease in the brain pO2 after hematocrit dropped to 30%. In animals with an initially low pO2 (13.1 +/- 1.7 mm Hg), this parameter decreased more slowly than in rats with a higher basic pO2 (24.5 +/- 1.7 mm Hg).     

Changes in the ultrastructure of the cerebral cortex in rats during learning and in disorders of higher nervous activity]

The results are outlined of a complex study of the ultrastructure of the rat cerebral cortex after learning and higher nervous activity disturbance. In the case of learning with preliminary stimulation with al-amphetamine or without it, the subcortical processes in the motor and auditory analysers of the cerebral cortex are characterized by sharp structural-functional activation of the apparatus of energy supply, of protein synthesis and of the synaptic zones. The length of the synaptic active zones increases, and extensive development of spine apparatuses is recorded in the postsynaptic area in the form of intricate membrane complexes. Quite the contrary, in cases of higher nervous activity disturbances, destruction of the organelles and desintegration of spine apparatuses is clearly pronounced. The question of the role of the latter in the memory processes is discussed.     

Effect of preliminary neurosensitization of rats on the postnatal development of the cerebral cortex of the progeny

The author investigated the cerebral cortex of 30-day ratlings born of rats preliminarily neurosensitized with a homologous cerebral cortex antigen, and of intact, control rats. In comparison with control, there was a reduction of the width of the sensory-motor region of the cortex, chiefly on account of the lower layers, diminution of the size of cell bodies of large neurons in the layer, inadequate development of the cytoplasm, and retarded accumulation of basophilic substance in it.     

Changes in the Na, K-ATPase of neuronal membranes in penicillin-induced epileptic foci in the cerebral cortex of the rat]

The relationship between electrophysiological changes and Na, K-ATPase activity of neuronal membranes in sodium penicillin-induced epileptic foci was studied. Na,K-ATPase activity is inhibited both in the primary focus and in homotopic contralateral area during latent period and in the stage of forming epileptic activity. In the stage of marked convulsive activity Na, K-ATPase is inhibited only in the primary focus. It is shown that penicillin at a concentration range of 2 x 10(-6)--2 x 10(-3) M does not influence Na,K-ATPase activity of crude synaptosomes of the rat brain cortex. It is suggested that Na,K-ATPase inactivation may serve as a pathogenetic factor in the development of convulsive process.     

Membrane bodies in the nuclei of cerebral cortex neurons of the progeny of rats sensitized to brain antigen

The ultrastructure of sensomotor cortical neurons was studied by electron microscopy in young rats born to females sensitized with brain antigen before mating. Different membranous inclusions were discovered in neuronal nuclei. The membranous bodies were seen on the second day after birth and could be detected until day 60. It is suggested that the nuclear membranous bodies have been formed in the prenatal period. They may be the result of intraplacental impact of neuroantibodies on the developing embryonic brain.     

Ultrastructural changes in the cerebral cortex following transcranial micropolarization]

Electron microscopy of the cerebral cortex in cats and monkeys following transcranial micropolarization (TCMP) demonstrated ultrastructural changes whose degree was dependent on the electric current intensity and the stimulation period. In the focus of stimulation the current affected the brain tissue directly, different elements of the cerebral cortex showing unegual sensitivity to various TCMP regimens. The glia was the first to respond, then the neuronal bodies, and the last -- the synaptic structures. In the areas distant from the TCMP focus synaptic components altered first. The ultrastructural changes revealed were not of pathological character.     

Changes in the electric activity of the cerebral cortex in poisoning caused by Cl. perfringens toxin type A]

The electrical activity of the cerebral cortex was recorded in cats under mild nembutal anesthesia (15-20 mg/kg of body weight) during the development of Cl. perfringens, type A, toxin poisoning (the toxin was injected intramuscularly in a dose of 100 MLD per kg of body weight). Two phases of the changes in the electrical activity of the cerebral cortex were noted. The first phase was attended by the desynchronization of the electrical activity, persistence of the induced potentials and of the reaction of the rhythm reconstruction to the rhythmic light stimulus. No desynchronization occurred under conditions of preliminary section of the midbrain (on the mesencephalic preparation), this indicating the involvement of the reticular formation into the pathological process and pointing to its role in the desynchronization effect. A profound depression of the electrical activity of the brain, depression of induced potentials and disturbance of the reaction of the rhythm reconstruction occurred during the second phase.     

Ovarian changes in the progeny of females subjected to prolonged cooling

The ovaries of immature offspring of the females, subjected to cooling (+5 degrees-+7 degrees C) for 80 days (including pregnancy period) have been investigated. As a control the ovaries of immature offspring of the females, living in the vivarium have been studied. By means of the light optic, electron microscopic, fluorescent-histochemical and morphometric methods, analysis of the generative structures and activity of the sympathetic innervation of the ovaries of performed. Ultramicroscopic organization of ovocytes with early signs of destruction is examined. In the animals of the test group total number of follicles and indices of sympathetic mediation of the ovaries decrease, while more than two-fold increase of ovocytes with signs of destruction is noted, predominantly in the primordial follicles. Thus, a prolonged adaptation of the female to cooling results in certain changes of the ovarian reproductive function in the offspring.     

Dynamics of axonal degeneration in the neuronally isolated cerebral cortex]

The brains of 11 cats were studied after unilateral isolation of the cortex after M. M. Khananashvily (1961) by means of resection of the projection fibres connecting the cortex with subcortical formations. The character and peculiarities of axonal degeneration in the large hemisphere cortex, were investigated after Nauta and Fink--Heimer. It was found that distribution of degenerating terminals in every layer depended on the time when the material was taken for investigation. Maximal concentration of the degenerating fibres was observed 3--5--10 days after the operation, then a gradual decrease in density of degeneration in every cortical layer was observed. By the 9th month after the operation, the processes of axonal degeneration completely came to their end. The problem of retrograde and anterograde nature of the axonal degeneration in the cortex of the large hemispheres was discussed in the article and it was demonstrated that in the field 4 of the neuronally isolated cortex it is of mixed nature.     

Anoxia-induced changes in cAMP contents in the cat cerebral cortex]

Effect of the cessation of oxygen supply on cAMP content and neuronal spike activity (NSA) in the cortex brain was studied. The interruption of oxygen supply during in first decades of seconds evoked changes in the pattern of NSA, followed with the decrease of cAMP content (to 56 +/- 10%). Then the phase of neuronal hyperactivity and increase of cAMP level (to 198 +/- 26%) took place. The content of cAMP approximated the basal one in 2.5 min anoxia. Anoxia during 5 min resulted in direct opposite shifts of cAMP content in two groups of cats (an increase up to 223 +/- 11%, and decrease up to 75 +/- 8%, respectively, which correlated with individual features of NSA recovery in postanoxic period and values of cAMP basal level in the cortex of different animals. Upon 30 min reoxygenation after 2.5 min anoxia a decline of the content of cAMP (to 63 +/- 12%) accompanied enhance of NSA. This period of reoxygenation after 5 min anoxia demonstrated two types of reactions, observed in different groups of cats: the first type--NSA tended to normalization with the level of cAMP 44 +/- 8% below basal level, and the second type--insufficient recovery of NSA attended by value of cAMP 90 +/- 13% above basal level.     

Persistence of females that produce only female progeny in lepidoptera

In Lepidoptera females that produce only female progeny, can be found in wild populations of at least 11 species. The genetic variation is passed on to each generation of female offspring. If genetically abnormal females produce more female offspring than normal females do and mating is random, then populations containing these abnormal females will have a biased population sex ratio. Unmated females will increase due to the scarcity of males and so the population as a unit will die out. Several possible biological explanations for the persistence of the genetic variation have been proposed. But experiments and observations have not verified those hypotheses. Simulations of Heuch's model (1978), however, have shown that the variation persists if the population is distributed, in patches and there is dispersal among patches, even when insects disperse at random. Abnormal females tend to persist at both low and high migration rates, but the probability of persistence is higher at high migration rates. It has been suggested that abnormal females in a population are an adaptation, but the results of this investigation show that this explanation, may not be plausible.     

Effect of maternal hypoxia on the neurogenesis of the cerebral cortex of rat progeny (autoradiographic study)]

Rats with 15-day pregnancy were exposed to two-hour hypoxia corresponding to 8,000 m altitude. On the 18th day of pregnancy they were administered thymidine-3H three times. Quantitative autoradiographic studies were performed on brain cortex neurons of 30-day rat progeny. The animals who had sustained intrauterine hypoxia were shown to have obviously higher number of labeled neurons in IId, IIId and Vth layers of the sensomotor area than controls. Differences in the label intensity were also revealed. It is suggested that maternal hypoxia may delay differentiation and maturation of the brain cortex neurons in the progeny.     

Neurospecific protein S-100 in the synaptosomes of rat cerebral cortex]

Neurospecific S-100 protein was revealed by the methods of microelectrophoresis in the 15% polyacrylamide gel with a 0.1% sodium dodecylsulfate and by a highly purified S-100 protein "marker" in the composition of low molecular acidic proteins of the rat brain synaptosomes. The S-100 protein conten constitutes about 15-2o% of the low molecular acidic synaptosomal porteins in the rat brain.