Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Nitric oxide (NO) is a small, diffusible, highly reactive molecule with a dichotomous regulatory role in the brain: an intra- and intercellular messenger under physiological conditions and a neurodegenerative agent under pathological conditions. We have recently demonstrated that long-lasting exposure to an neuronal nitric oxide synthase (nNOS) inhibitor down-regulated serine/threonine kinase (Akt) survival pathway and caused apoptosis in cerebellar granule cell cultures. The present study further substantiates the role of NO in neuronal survival by demonstrating that blocking its production down-regulates the activity of cAMP-responsive element binding protein (CREB), a transcription factor involved in cell survival and synaptic plasticity. Pharmacological dissection of the pathway linking NO to CREB shows that cGMP and its kinase are intermediate effectors. We also identify Bcl-2 as one of the anti-apoptotic genes down-regulated by NO shortage and decreased CREB phosphorylation. These results not only confirm the role of CREB in neuronal survival but also provide circumstantial evidence for a novel link among NO, CREB activation and survival.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 81 (2002), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Apoptotic death results from disrupting the balance between anti-apoptotic and pro-apoptotic cellular signals. The inter- and intracellular messenger nitric oxide is known to mediate either death or survival of neurones. In the present work, cerebellar granule cells were used as a model to assess the survival role of nitric oxide and to find novel signal transduction pathways related to this role. It is reported that sustained inhibition of nitric oxide production induces apoptosis in differentiated cerebellar granule neurones and that compounds that slowly release nitric oxide significantly revert this effect. Neuronal death was also reverted by a caspase-3-like inhibitor and by a cyclic GMP analogue, thus suggesting that nitric oxide-induced activation of guanylate cyclase is essential for the survival of these neurones. We also report that the Akt/GSK-3 kinase system is a transduction pathway related to the survival action of nitric oxide, as apoptosis caused by nitric oxide deprivation is accompanied by down-regulation of this, but not of other, kinase systems. Conversely, treatments able to rescue neurones from apoptosis also counteracted this down-regulation. Furthermore, in transfection experiments, overexpression of the Akt gene significantly decreased nitric oxide deprivation-related apoptosis. These results are the first evidence for a mechanism where endogenous nitric oxide promotes neuronal survival via Akt/GSK-3 pathway.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 98 (1994), S. 421-430 
    ISSN: 1432-1106
    Schlagwort(e): Fos protein induction ; Neuropathology ; Kainic acid ; N-Methyl d-aspartate Pharmacological protection ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The excitotoxins kainic acid and N-methyl d-aspartate (NMDA) were unilaterally injected in the rat striatum. Kainic acid injections resulted in a widespread pattern of Fos protein induction, mainly involving cortical olfactory structures and hippocampus. Immunoreactive cells were observed in large number 2–24 h after injection and had almost completely disappeared by 48 h. NMDA injections elicited a shorter (2–8 h) expression of Fos protein, involving a lower number of cells in cortical olfactory structures, a much larger number of cells in the other cortical regions, and not involving the hippocampus at all. Characteristically none of the two excitotoxins stimulated Fos expression from striatal neurons, even in the close vicinity of the needle tract. In addition to striatal lesions almost equivalent in size, the two excitotoxins caused distant lesions of different extension: kainic acid resulted in extensive neuronal degeneration in the olfactory-entorhinal cortices and among pyramidal neurons of the hippocampus; NMDA caused a less widespread neurodegeneration, restricted to the olfactory cortex. Administration of the competitive NMDA antagonist CGP 39551 largely prevented the distant, but not the local, neuropathological changes caused by intrastriatal kainic acid or NMDA. The expression of Fos protein, however, was partially prevented only in NMDA cases. The present results show a good relationship between the spreading of circuit overexcitation caused by the two excitotoxins and the regional and temporal patterns of Fos expression. The relationship between Fos expression and neuropathological condition remains, however, elusive.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    ISSN: 1432-1106
    Schlagwort(e): Key words Oncogene expression ; Polyamines ; Neuropathology ; Apoptosis ; Olfactory cortex ; Hippocampus ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Microencephalic rats obtained by gestational treatment with the DNA alkylating agent methylazoxymethanol, show a remarkable lack of sensitivity to excitotoxic neuropathology caused by systemic injections of the convulsant neurotoxin kainic acid. Taking advantage of this, we have studied in these rats, as well as in normal rats, the relationship between the induction of cellular signals supposedly related to cell death and the neuronal apoptosis consequent to kainic acid administration. While normal rats responded to the excitatory insult with a large and relatively long lasting increase of the activity of the enzyme ornithine decarboxylase and of the concentration of putrescine in some brain regions, these alterations were much smaller in microencephalic rats. Expression of c-fos in brain regions sensitive to kainic acid was quicker but lasted a noticeably shorter time in microencephalic rats as compared to normal animals. A profusion of apoptotic neurons, labeled by an in situ technique, were observed in the olfactory cortex, amygdala and hippocampus of normal rats injected with kainic acid, in particular 48 h and 72 h after drug administration. At corresponding time intervals and with similar topographic localization, neurons expressing p53 protein were observed. By contrast, microencephalic rats displayed only in a few cases and in a small number apoptotic neurons in restricted areas of the ventral hippocampus and entorhinal cortex. Noticeably, in these cases small populations of p53-expressing neurons were also present in the same areas. The present observations clearly show that oncogenes such as c-fos and p53, as well as ornithine decarboxylase which behaves as an immediate-early gene in the brain under certain circumstances, undergo noticeably lower and/or shorter induction in microencephalic rats exposed to excitotoxic stimuli. In these rats, therefore, the cellular signalling pathways studied here and related to excitotoxic sensitivity and committment to cell death are downregulated as a probable consequence of altered brain wiring.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...