The participation of the striatum in the central regulation of gonadal hormonal function]

Intrastriatal corticotrophin-releasing hormone (CRH) was shown to induce a decrease in the plasma tectosterone concentration. Besides, the 6-OHDA pre-treatment completely prevented the suppression of plasma testosterone in response to intrastriatal CRH administration. The findings suggest that the striatum is involved in the extrahypothalamic regulation of the gonadal endocrine function.     

The effect of administering corticoliberin into the striatum on the open-field and shuttle-box behaviors of KHA and KLA strain rats]

The effects of corticotropin-releasing hormone (CRH) injected into the dorsal neostriatum on the open-field and shuttle-box behavior were studied in rats with high (Koltushi high avoidance, KHA) and low (Koltushi low avoidance, KLA) capability for avoidance learning. The effects of this hormone on the behavior of these rat strains were different. In KLA rats with passive strategy of behavior the CRH injection led to a rapid locomotor activation in the open field, while the rats with active behavioral strategy (KHA) reacted to the injection by a significant decrease in locomotion and change for the passive mode of behavior. The same CRH effects on locomotion were obtained in the shuttle-box experiments. Moreover, in the KLA rats the neurohormone injection resulted in an improvement of avoidance learning in contrast to the KHA rats, in which CRH substantially impaired avoidance learning. The obtained evidence is discussed in terms of the important role of striatal CRH in the choice of behavioral strategy in stress.     

Plant virus infection development as affected by heavy metal stress

The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants.     

Increased expression of peripheral benzodiazepine receptors and diazepam binding inhibitor in human tumors sited in the liver

The peripheral benzodiazepine receptor system triggers intracellular metabolic events and has been associated with cell proliferation. Its endogenous ligand, the diazepam binding inhibitor, contributes to steroidogenesis by promoting cholesterol delivery to the inner mitochondrial membrane. The present study was undertaken to verify whether this system is altered in tumors sited in the liver. Peripheral benzodiazepine receptors and diazepam binding inhibitor were studied using immunocytochemistry and in situ hybridization in 9 human tumors sited in the liver, in liver hyperplasia, cirrhotic nodular regeneration, intestinal adenocarcinoma and in surrounding non-tumoral tissue. Immunocytochemical staining and in situ hybridization demonstrated that peripheral benzodiazepine receptors and diazepam binding inhibitor were more prominently expressed in neoplastic cells than in non-tumoral tissue. They were present in the same cells, suggesting that diazepam binding inhibitor may act in an intracrine manner in these cells. Higher peripheral benzodiazepine receptors and diazepam binding inhibitor expression in tumor cells suggest an implication of this system in the metabolism of neoplastic cells. Furthermore the evaluation of peripheral benzodiazepine receptor and diazepam binding inhibitor expression might be useful in evaluating malignancy and in diagnostic approaches of tumors in liver tissue.     

Dynamics of hypothalamic CRH immune reactivity in active and passive rats in the course of development of behavioural depression

A possible relation between activity of the main CRH-producing centers of hypothalamus and depressive-like behavior of animals was studied. We used genetically selected strains--KHA (Koltushi High Avoidance) and KLA (Koltushi Low Avoidance) rats, demonstrating active and passive strategy of adaptive behavior in novelty situaltions, respectively. Rats were exposed to inescapable stress to develop a "learned helplessness". We observed considerable differences between two strains of animals in CRH-expression in parvo-, magno-cellular parts of the paraventricular nucleus and in the supraoptic nucleus in the course of behavioral depression development. Significant differences between control groups were seen only in paraventricular nucleus. On the 1st post-stress day in hypothalamus of KLA rats, we detected decreased CRH immune reactivity that remained unchanged up to the 10th day. In KHA rats, there were no notable changes of CRH expression in all studied nuclei. These findings, including previous results on different dynamics of behavioral changes and different hypothalamo-pituitary-adrenocortical system activity during development of depression in KLA and KHA rats, indicate that "learned helplessness" in these two groups of animals provides the model analogues of different types of depression. Besides, these findings indicate different implication of hypothalamus CRH-system in the behavioral depression development in rats with divergent strategy of adaptive behavior.     

Multivariate morphometric analysis of Pacific herring, <Emphasis Type="Italic">Clupea pallasii</Emphasis> (Clupeiformes: Clupeidae) in Sakhalin waters: Investigation of intraspecific differentiation

In the Pacific herring, Clupea pallasii, eight samples of spawning, mature fish (collected in 1978 and 1981) and six samples of immature fish individuals (collected in 1979, 1980 and 1984) were analyzed. Mature fish were analyzed by 24 conventional morphometric characters or morphometric indices. By means of discriminant and factor analyses (principal component mode) the existence of differentiating groupings of vector scores was found that have obvious biological meaning as local Pacific herring stocks. In concordance with former morphobiological and genetic data, current multivariate observations supported the existence in the surveyed area of Sakhalin waters of at least three stocks. One of them is the Sakhalin-Hokkaido local stock of Pacific herring, which in the past provided the bulk of herring catches in the region and showed a distinct and sharper morphometric differentiation as compared with other herring assemblages.     

Patterns of molecular and phenotypic diversity in pearl millet [<Emphasis Type="Italic">Pennisetum glaucum</Emphasis>(L.) R. Br.] from West and Central Africa and their relation to geographical and environmental parameters

Background  

The distribution area of pearl millet in West and Central Africa (WCA) harbours a wide range of climatic and environmental conditions as well as diverse farmer preferences and pearl millet utilization habits which have the potential to lead to local adaptation and thereby to population structure. The objectives of our research were to (i) assess the geographical distribution of genetic diversity in pearl millet inbreds derived from landraces, (ii) assess the population structure of pearl millet from WCA, and (iii) identify those geographical parameters and environmental factors from the location at which landraces were sampled, as well as those phenotypic traits that may have affected or led to this population structure. Our study was based on a set of 145 inbred lines derived from 122 different pearl millet landraces from WCA.     

The extrahypothalamic level of the hypophyseal-adrenocortical system regulation appears to be involved in development of different types of depression-like state in rats

Possible role of extrahypothalamic corticotrophin-releasing hormone (CRH) and vasopressin-producing centers in post-stress depression development were studied. We used genetically selected strains: KHA (Koltushi High Avoidance) and KLA (Koltushi Low Avoidance) rats developing different types of depression in the "learned helplessness" paradigm: the model analogues of endogenous (KHA strain) and exogenous (KLA strain) depression. Interstrain differences of control and stress-induced CRH- and vasopressin-expression in hippocampus and neocortex in the course of depression development in KHA and KLA rats were revealed using immuno-histochemical studies. It has been shown that a significant increase of CRH- and vasopressin-immune reactivity in hippocampus and neocortex of KHA rats occurred on the 10th post-stress day. We detected also decreased CRH- and vasopressin-expression in dorsal hippocampus, and increased CRH-immune reactivity in neocortex of KLA rats in the same post-stress period. These findings imply that extrahypothalamic CRH- and vasopressin-ergic systems appear to be involved in pathogenesis mechanisms of model analogues of endogenous and exogenous depression in different ways.