Show simple item record Souza, Marta Marques de Gross, Sascha Boyle, Robert Tew Lieberman, Melvyn 2011-06-30T02:38:48Z 2011-06-30T02:38:48Z 2000
dc.identifier.citation SOUZA, Marta Marques de et al. Na+/K+-ATPase inhibition during cardiac myocyte swelling: Involvement of intracellular pH and Ca2+. Molecular and Cellular Biochemistry, Netherlands, v. 210, p. 173-183, 2000. Disponível em: <>. Acesso em: 17 jun. 2011. pt_BR
dc.identifier.issn 0300-8177
dc.description.abstract Previous studies in chick embryo cardiac myocytes have shown that the inhibition of Na+/K+-ATPase with ouabain induces cell shrinkage in an isosmotic environment (290 mOsm). The same inhibition produces an enhanced RVD (regulatory volume decrease) in hyposmotic conditions (100 mOsm). It is also known that submitting chick embryo cardiomyocytes to a hyperosmotic solution induces shrinkage and a concurrent intracellular alkalization. The objective of this study was to evaluate the involvement of intracellular pH (pHi), intracellular Ca2+ ([Ca2+]i) and Na+/K+-ATPase inhibition during hyposmotic swelling. Changes in intracellular pH and Ca2+ were monitored using BCECF and fura-2, respectively. The addition of ouabain (100 μM) under both isosmotic and hyposmotic stimuli resulted in a large increase in [Ca2+]i (200%). A decrease in pHi (from 7.3 ± 0.09 to 6.4 ± 0.08, n = 6; p < 0.05) was only observed when ouabain was applied during hyposmotic swelling. This acidification was prevented by the removal of extracellular Ca2+. Inhibition of Na+/H+ exchange with amiloride (1 mM) had no effect on the ouabain-induced acidification. Preventing the mitochondrial accumulation of Ca2+ using CCCP (10 μM) resulted in a blockade of the progressive acidification normally induced by ouabain. The inhibition of mitochondrial membrane K+/H+ exchange with DCCD (1 mM) also completely prevented the acidification. Our results suggest that intracellular acidification upon cell swelling is mediated by an initial Ca2+ influx via Na+/Ca2+ exchange, which under hyposmotic conditions activates the K+ and Ca2+ mitochondrial exchange systems (K+/H+ and Ca2+/H+). pt_BR
dc.language.iso eng pt_BR
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dc.subject Na+/K+-ATPase pt_BR
dc.subject Hyposmotic swelling pt_BR
dc.subject Intracellular pH pt_BR
dc.subject Intracellular Ca2+ pt_BR
dc.subject Mitochondrial transporters pt_BR
dc.title Na+/K+-ATPase inhibition during cardiac myocyte swelling: Involvement of intracellular pH and Ca2+ pt_BR
dc.type article pt_BR

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