Andrzej Beręsewicz

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Brain L-glutamine (Gln) accumulation and increased activity of the NO/cGMP pathway are immediate consequences of acute exposure to ammonia. This study tested whether excess Gln may influence NO and/or cGMP synthesis. Intrastriatal administration of the glutaminase inhibitor 6-diazo-5-oxo-L-norleucine or the system A-specific Gln uptake inhibitor(More)
One of the aspects of ammonia toxicity to brain cells is increased production of nitric oxide (NO) by NO synthases (NOSs). Previously we showed that ammonia increases arginine (Arg) uptake in cultured rat cortical astrocytes specifically via y(+)L amino acid transport system, by activation of its member, a heteromeric y(+)LAT2 transporter. Here, we tested(More)
Ammonia neurotoxicity is associated with overactivation of N-methyl-D-aspartate (NMDA) receptors leading to enhanced nitric oxide and cyclic GMP synthesis and to accumulation of reactive oxygen and nitrogen species. Ammonia is detoxified in the brain via synthesis of glutamine, which if accumulated in excess contributes to astrocytic swelling, mitochondrial(More)
UNLABELLED Iron and copper toxicity has been presumed to involve the formation of hydroxyl radical (*OH) from H2O2 in the Fenton reaction. The aim of this study was to verify that Fe2+-O2 and Cu+-O2 chemistry is capable of generating *OH in the quasi physiological environment of Krebs-Henseleit buffer (KH), and to compare the ability of the Fe2+-O2 system(More)
In isolated myocytes from mammalian ventricles a fast and a slow component in the contractile response to depolarizing voltage clamp steps were identified. The potential dependence of the slow component was identical to the activation curve of iCa. The fast component, however, remained at its maximal amplitude at potentials positive to +10 mV (up to +100(More)
Iron and copper toxicity has been presumed to involve the formation of hydroxyl radical (. 2+ and Cu + (0–20 mM) to KH resulted in a concentration-dependent increase in. OH formation , as measured by the salicylate method. While Fe 3+ and Cu 2+ (0–20 mM) did not result in. OH formation, these ions mediated significant. OH production in the presence of a(More)
We hypothesized that, due to a cross-talk between cytoplasmic O2--sources and intraluminally expressed xanthine oxidase (XO), intraluminal O2- is instrumental in mediating intraluminal (endothelial dysfunction) and cytosolic (p38 and ERK1/2 MAPKs phosphorylation) manifestations of vascular oxidative stress induced by endothelin-1 (ET-1) and angiotensin II(More)
We have studied changes in electrical activity resulting from abrupt alterations of the Na gradient, using ventricular myocytes isolated from feline and bovine hearts. Attempting to investigate the ionic current possibly generated by Na-Ca exchange, we studied the effects of the changes in [Na]o in the presence of 20 mM CsCl to inhibit K currents. To(More)
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