Sabine Fischer

Philipps University of Marburg, Marburg, Hesse, Germany

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Publications (2)7.07 Total impact

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    ABSTRACT: Antidepressants (AD) (desipramine, imipramine, maprotiline, mirtazapine) and corticosteroid (CS) were examined for their effects on gene expression in human monocytic U-937 blood cells. Endocrine and signaling-related response patterns were determined by expression analysis of different factors, comprising endocrine (glucocorticoid receptor [GR], GR-alpha/beta/gamma; mineralocorticoid receptor [MR]) and signaling-related pathways (p105, STAT3, c-jun, c-fos, JNK1, GAPDH, TNF-alpha). A semiquantitative RT-PCR for factor responses after 24 h of treatment was conducted and exploratory multivariate statistical procedures were applied for further analysis. Compared to controls, significant reduction of mRNA levels of GR-beta under imipramine and of c-jun under desipramine treatment were found. CS treatment significantly reduced mRNA levels of GR-alpha/beta, TNF-alpha, p105 and c-jun compared to controls. Compared to CS treatment, significantly increased mRNA levels were found for JNK1 under imipramine treatment and for GR-alpha after treatment with all AD examined. The multivariate approach meets the requirements of the complex situation of metabolic reactions induced by AD or CS treatment. Our data show that AD affect both, endocrine and signaling-related factors in human monocytic U-937 blood cells, although clearly not in a uniform manner. Hereby, GR is obviously playing a comparably central role. Overall, AD treatment might indeed normalize deviations of cellular endocrine and signaling-related pathways in major depressive disorder via the mechanisms examined.
    No preview · Article · Aug 2008 · Progress in Neuro-Psychopharmacology and Biological Psychiatry
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    ABSTRACT: Neurocellular overload with hydrogen peroxide (H2O2) induces oxidative stress and may initiate a cascade of intracellular toxic events leading to energy failure, increased lipid peroxidation and subsequently cell death. Studies suggest that hippocampal neurons may be more vulnerable to oxidative stress than cortical cells pointing to a differential vulnerability of neuronal cells. Since disturbed ATP- and calcium (Ca2+)-metabolism may be involved in this process, we here evaluated the effects of H2O2-induced oxidative stress and the involvement of Ca2+-regulation on neuronal energy metabolism. Using primary cortical and hippocampal neurons as well as immortalized hippocampal HT22 cells, we determined ATP-levels and accompanying cell death after oxidative challenge with H2O2. Additionally, the combined effects of H2O2 and alterations in Ca2+-concentrations were pharmacologically characterized in more detail. H2O2-incubation decreased ATP-levels in a dose- and time-dependent manner in all neuronal cell systems tested. Such effects were most pronounced in primary hippocampal neurons. In cortical cells, increased ATP-levels were notable under low H2O2-concentrations. A dose-dependent decrease in ATP-concentrations was observed after treatment with Ca2+, which was further enhanced by additional H2O2-challenge. Our data underline that both, H2O2- and Ca2+-treatment, are able to disturb intracellular energy metabolism. Out of the different systems studied, the ATP-decrease is most pronounced in hippocampal primary neurons, suggesting that this mechanism contributes to the selective neuronal vulnerability to oxidative stress in these neurons.
    No preview · Article · Feb 2007 · NeuroToxicology