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Opioid peptide gene expression in the primary hereditary cardiomyopathy of the Syrian hamster .2. Role of intracellular calcium loading
No full textWe have previously shown that prodynorphin gene expression was markedly increased in adult myocytes of BIO 14.6 cardiomyopathic hamsters and that nuclear protein kinase C (PKC) may be involved in the induction of this opioid gene, Here we report that the cytosolic Ca2+ concentration was significantly increased in resting and in KCl-depolarized cardiomyopathic myocytes compared with normal cells, In normal and in cardiomyopathic cells, KCl significantly increased prodynorphin mRNA levels and prodynorphin gene transcription, These effects were abolished by the Ca2+ channel blocker verapamil. In control myocytes, the KCl-induced increase in prodynorphin mRNA expression was in part attenuated by chelerythrine or calphostin C, two selective PKC inhibitors, In these cells, KCL induced the translocation of PKC-alpha into the nucleus, increasing nuclear PKC activity, In resting cardiomyopathic myocytes, the increase in prodynorphin mRNA levels and gene transcription were significantly attenuated by the intracellular Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethylester being completely abolished when the chelating agent was administered in the presence of PKC inhibitors, KCI and the PKC activator 1,2-dioctanoyl-sn-glycerol additively stimulated prodynorphin gene expression both in normal and in cardiomyopathic cells, Therefore, we conclude that PKC activation and intracellular Ca2+ overload may represent the two major signaling mechanisms involved in the induction of the prodynorphin gene in cardiomyopathic cells
Gamma-oryzanol, a component for cosmetic formulations: in vitro studies of antioxidant activity
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Gamma-oryzanol, a main component of rice bran oil: in vitro studies of its antioxidant properties
No full textNuclear opioid receptors activate opioid peptide gene transcription in isolated myocardial nuclei
No full textOpioid-binding sites were identified in highly purified nuclei isolated from hamster ventricular myocardial cells. A significant increase in the maximal binding capacity for a kappa opioid receptor ligand was observed in myocardial nuclei from BIO 14.6 cardiomyopathic hamsters, as compared with nuclei obtained from normal myocytes of the F1B strain. The exposure of isolated nuclei to dynorphin B, a natural agonist of kappa opioid receptors, markedly increased opioid peptide gene transcription. The transcriptional effect was mediated by nuclear protein kinase C activation and occurred at a higher rate in nuclei from cardiomyopathic myocytes than in nuclei isolated from normal cells. Thus, a nuclear endorphinergic system may play an intracrine role in the regulation of gene transcription under both normal and pathological conditions
Valutazione dei meccanismi molecolari attraverso i quali una sostanza naturale esercita la propria attività antiossidante
No full textSpectrophotometric measurement of hydroperoxides by oxidation of Fe2+ in the presence of Xylenol Orange
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