caa a22 4500 445853786 CHVBK 20180317145422.0 cr unu---uuuuu 170323e20110801xx s 000 0 eng 10.1007/s00204-010-0630-9 doi (NATIONALLICENCE)springer-10.1007/s00204-010-0630-9 Structural isomerization of synephrine influences its uptake and ensuing glutathione depletion in rat-isolated cardiomyocytes [Elektronische Daten] [Luciana Rossato, Vera Costa, Paula de Pinho, Félix Carvalho, Maria de Lourdes Bastos, Fernando Remião] Synephrine is a natural compound, frequently added to ephedra-free dietary supplements for weight-loss, due to its effects as a nonspecific adrenergic agonist. Though only p-synephrine has been documented in plants, the presence of m-synephrine has also been reported in weight-loss products. The use of synephrine in dietary supplements was accompanied by reports of adverse effects, especially at the cardiovascular level. It is well known that the imbalance in cardiac glutathione levels can increase the risk of cardiomyopathy. The present work aimed to study the role of organic cation-mediated transport of m- and p-synephrine and the possibility that p- and m-synephrine induce intracellular changes in glutathione levels in calcium-tolerant freshly isolated cardiomyocytes from adult rat. After a 3h incubation with 1mM p- or m-synephrine, the intracellular content of synephrine was measured by gas chromatography/ion trap-mass spectrometry (GC/IT-MS); cell viability and intracellular glutathione levels were also determined. To evaluate the potential protective effects of antioxidants against the adverse effects elicited by m-synephrine, cells were pre-incubated for 30min with Tiron (100μM) or N-acetyl-cysteine (NAC) (1mM). To assess the influence of α1-adrenoceptors activation in glutathione depletion, a study with prazosin (100nM) was also performed. The results obtained provide evidence that organic cation transporters OCT3 and OCT1 play a major role in m- and p-synephrine-mediated transport into the cardiomyocytes. The importance of these transporters seems similar for both isomers, although p-synephrine enters more into the cardiomyocytes. Furthermore, only m-synephrine induced intracellular total glutathione (GSHt) and reduced glutathione (GSH) depletion. NAC and Tiron were able to counteract the m-synephrine-induced GSH and GSHt decrease. On the other hand, the incubation with prazosin was not able to change m-synephrine-induced glutathione depletion showing that this effect is independent of α1-adrenoceptor stimulation. In conclusion, both positional isomers require OCT3 and OCT1-mediated transport to enter into the cardiomyocytes; however, the hydroxyl group in the p-position favours the OCT-mediated transport into cardiomyocytes. Furthermore, the structural isomerization of synephrine influences its toxicological profile since only m-synephrine caused GSH depletion. Springer-Verlag, 2010 Synephrine nationallicence Phenylephrine nationallicence Rat cardiomyocytes nationallicence Organic cation transporter nationallicence Glutathione depletion nationallicence CORT : Corticosterone nationallicence DMSO : Dimethyl sulphoxide nationallicence DTNB : 5,5-dithio-bis(2-nitrobenzoic acid) nationallicence FDA : Food and Drug Administration nationallicence GC/IT-MS : Gas chromatography/ion trap-mass spectrometry nationallicence GR : Glutathione reductase nationallicence GSH : Reduced glutathione nationallicence GSHt : Total glutathione nationallicence GSSG : Glutathione disulphide nationallicence HClO4 : Perchloric acid nationallicence HEPES : N-(2-hydroxyethyl) piperazine-N-(2-ethanesulphonic acid) nationallicence IS : Internal standard nationallicence LDH : Lactate dehydrogenase nationallicence MRP1 : Multidrug resistance protein 1 nationallicence NAC : N-acetyl-cysteine nationallicence NADPH : Reduced nicotinamide adenine dinucleotide phosphate nationallicence OCT : Organic cation transporter nationallicence OCTN : Novel organic cation transporter nationallicence PMAT : Plasma membrane monoamine transporter nationallicence QUIN : Quinidine nationallicence ROS : Reactive oxygen species nationallicence SD : Standard deviation nationallicence SPE : Solid-phase extraction nationallicence TFAA : Trifluoroacetic anhydride nationallicence Tiron : 4,5-dihydroxy-1,3-benzene disulphonic acid nationallicence β-NADH : Reduced β-nicotinamide adenine dinucleotide nationallicence Rossato Luciana REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut Costa Vera REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut de Pinho Paula REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut Carvalho Félix REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut de Lourdes Bastos Maria REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut Remião Fernando REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut Archives of Toxicology Springer-Verlag 85/8(2011-08-01), 929-939 0340-5761 85:8<929 2011 85 204 https://doi.org/10.1007/s00204-010-0630-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00204-010-0630-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Rossato Luciana REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut NATIONALLICENCE 700 1- Costa Vera REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut NATIONALLICENCE 700 1- de Pinho Paula REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut NATIONALLICENCE 700 1- Carvalho Félix REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut NATIONALLICENCE 700 1- de Lourdes Bastos Maria REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut NATIONALLICENCE 700 1- Remião Fernando REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal aut NATIONALLICENCE 773 0- Archives of Toxicology Springer-Verlag 85/8(2011-08-01), 929-939 0340-5761 85:8<929 2011 85 204 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer