Effects of infant rat fostering in artificially formed litters on the development of brain, adrenals and gonads.

Morphometric and histochemical properties of neurons in the frontoparietal and parietal lobes and CA1 hippocampal area, thickness of the neocortex, histochemical and morphometric properties of adrenals and gonads, and concentrations of sex hormones were compared in 40-day rats fostered in artificially formed (experimental group) and natural (control) litters. Animals of the experimental group had lower body and brain weight, thickness of the neocortex in the parietal lobe, sizes of nuclei and cytoplasm of layer 2 and layer 5 neurons of the frontoparietal and parietal lobes and in the hippocampus, lower NADPH-dehydrogenase activity in the hippocampus, and lower NADH- dehydrogenase activity in layer 2 neurons of the parietal lobe in comparison with control rats. RNA concentration in neuronal cytoplasm in neocortex and hippocampus was higher in rats from experimental group, than in animals from the control group. Higher estradiol concentration, higher activity of 3ß-hydroxysteroiddehydrogenase in thecal cells of ovarian follicles were found in females from experimental group; decreased testicle weight, reduced diameter of seminiferous tubules, reduced activity of 3ß-hydroxysteroiddehydrogenase in Leydig's cells, and trend forward lowering of testosterone concentration were found in males from experimental group.

Association of brain weight value with morphometric and histochemical properties of cortical neurons and higher nervous activity parameters in rats in prepubertal period.

We compared thickness of the neocortex, morphometric and histochemical characteristics of neurons in frontoparietal and parietal lobes and hippocampal field I in animals from great litters with lower brain weight (group 1) and from small (artificially reduced) litters with higher brain weight (group 2). It was found that the thickness of the neocortex in the frontoparietal and parietal lobes does not differ in the compared groups, while the size of neuronal cytoplasm in layer II of the frontoparietal and parietal lobes and in layer V of the frontoparietal lobe in group 2 animals was lower than in group 1. Nuclei of cortical neurons in layer II of the parietal and frontoparietal lobes and in frontoparietal lobe layer V in group 2 animals were smaller than in group 1. Neuronal nucleoli in group 2 animals were also smaller than in group 1 rats. RNA concentration in neuronal cytoplasm in the hippocampus and neocortex of group 2 rats was higher than in group 1 animals. NADPH-dehydrogenase activity in neurons of parietal lobe (layer II) and hippocampus in group 2 rats was lower than in group 1 animals, NADH-dehydrogenase activity was lower in parietal lobe layer II neurons. Group 2 rats demonstrated increased number of hanging down, sniffing, movements, entries into open and closed arms, and lower immobility time in the elevated plus-maze test.

Effect of long-term constant illumination of female rats on the parameters of brain development in their 40-day-old progeny.

We studied the progeny from female rats exposed to constant illumination for 1 month and mated with intact males 14 days after this exposure. At the age of 40 days, the progeny from experimental rats differed from the control by lower body weight, thickness of the adrenal cortex, and diameter of convoluted seminal tubules. The weight of the brain was similar in both groups. The thickness of the cortex in the parietal lobe, and especially, in the frontoparietal lobe was decreased; the neuronal density in these lobes (layers II and V) was reduced. In layer II and V neurons of the parietal lobe, the size of neuronal nuclei reduced, the concentration of RNA and activities of NADH and NADPH dehydrogenases in the cytoplasm were considerably increased. Elevated concentration of lipids was found in layer I of cerebral and cerebellar cortex and in the white matter, which attests to higher myelinization degree compared to the control.

[Peculiarities of ovarian and adrenal histophysiology in female rats producing the offspring with an accelerated brain development].

The purpose of the present study was to determine what peculiarities of endocrine and reproductive systems of female rats may favor the birth of the offspring with an accelerated brain development. The study included 20 female rats examined 1 day after the parturition and their 1-day-old offspring (n = 201). In females the activity of 3b-hydroxysteroid dehydrogenase (HSD) and lipid concentration were determined in ovarian steroid-producing structures and in all the zones of adrenal cortex. Estradiol and triiodothyronine concentrations were measured in blood and the prenatal mortality of the offspring was determined. In newborn rats the brain mass, neocortex and its layer I thickness were measured as well as the numerical density of neurons in layer V. Using the method of cluster analysis, newborn rats and their mothers were divided into 3 groups, depending upon the degree of brain development of the offspring. It was shown that an accelerated brain development was associated with somewhat smaller number of newborn rats per litter, an increased prenatal fetal loss, and lower HSD activity in ovarian and adrenal cortex steroid-producing cells, low estradiol concentration in blood. It is assumed that these peculiarities of maternal endocrine and reproductive systems could cause a higher level of brain development in their offspring.

Effect of the age of pregnant females on brain development in the offspring.

We examined offspring of 9-10 and 3.5-4 month-old female rats. Female offspring (14, 21, 28, 35, and 40 days) of old rats had higher body weight than offspring of young animals. No intergroup differences were revealed in the body weight of male offspring. At the age of 40 days the offspring of old females differed from the offspring of young rats by higher absolute weight of the brain (females), lower size of ganglionic neurons in the parietal lobe (males and females), and lower blood testosterone concentration (males). Thirty-day-old offspring of old rats exhibited higher locomotor activity and lower degree of anxiety compared to the offspring of young animals.

Effect of emotional stress experienced by female rats before pregnancy on brain development in their offspring.

Twenty-one- and 40-day-old offspring from female rats exposed to emotional stress for 3 weeks and mated with intact males 10 days later were examined. Intact female offspring served as the control. The weight of the brain of 21- and 40-day-old experimental rats varied is a wider range compared to the control. In 40-day-old experimental males, the mean weights of the brain and hemisphere were lower than in controls. In 21-day-old rats, layer V neuronal nuclei were enlarged, while the thickness of the parietal cortex tended to decrease. In 40-day-old animals, morphometric parameters of neurons in the neocortex and hippocampus and RNA concentration in their cytoplasm did not differ from the control. Thirty-day-old experimental rats demonstrated low exploratory activity in the plus-maze test.

Effect of emotional stress in pregnant rats on brain development of their progeny.

We compared 21- and 40-day old rat pups from rats subjected to emotional stress in trimester III and from intact females. The width of the parietal cortex and the size of layer V neuron cytoplasm and nuclei in the anterior parietal lobe and hippocampus were increased in 21-day-old test pups compared to age-matched controls. In 40-day-old test pups, neurons in layers II and V of the parietal lobe and layer II of the anterior parietal lobe and hippocampal neurons were enlarged compared to the control.

[Effects of opioid receptor ligands on DNA synthesis and histamine contents in the gastric mucosa and blood of white rats]. / Vliianie ligandov opioidnykh retseptorov na sintez DNK i soderzhanie gistamina v slizistoi zheludka i krovi belykh krys.

Using autoradiographic study with 3H-thymidine and spectrofluorometric method the authors studied the influence of opioid receptors' ligands on the DNA synthesis in the stomach epithelium histamine content and the blood. Leu-encephalin, B-endorphin, dalargin, napoxone were administered intraperitoneally to male rats. The dose of injection was 0.1 ml per 100 g body weight. It was observed that B-endorphin and dalargin 1.5-1.6 fold increased the quantity of DNA-synthesised nuclei in the epithelium of fundal stomach section. Leu-encephalin and dalargin increased the histamine concentration in the stomach, at the same time dalargin caused a rapid decrease of histamine concentration in the blood. Naloxone also decreased histamine concentration in the stomach. The obtained results are being discussed in connection with dalargin therapy of ulcerous diseases.

[Seasonal changes of corticosteroid content in practically healthy young persons under condition of monsoon climate of Khabarovsk]. / Sezonnye izmeneniia soderzhaniia kortikosteroidov u prakticheski zdorovykh molodykh liudei v usloviiakh mussonnogo klimata Khabarovska

In 195 apparently healthy young men, residents of Khabarovsk, a study was made of the contents of the sum total 11-OCS, corticosteroids--free and protein-bound, cortizol and corticosterone in the blood plasma, and 17-OCS in the urine, depending on the season of the year, climatic and weather factors. Seasonal changes of glucocorticoid function of the adrenal cortex with the maximal plasma hormone level during winter and their greatest urinary excretion during summer were found. An increase of free (biologically-active) corticosteroid fraction was recorded during bad weather at all the seasons.