Show simple item record Ruiz, Juliana Lopes Souza, Marta Marques de 2011-06-30T02:34:28Z 2011-06-30T02:34:28Z 2008
dc.identifier.citation RUIZ, Juliana Lopes ; SOUZA, Marta Marques de. Osmotic stress and muscle tissue volume response of a freshwater bivalve. Comparative Biochemistry and Physiology. A, Molecular & Integrative Physiology, v. 151, p. 399-406, 2008. Disponível em: <>. Acesso em: 17 jun. 2011. pt_BR
dc.identifier.issn 1095-6433
dc.description.abstract The freshwater bivalve, Corbicula fluminea, when submitted to hyperosmotic solutions, behaves as a hyperosmoconformer; we have observed an increase in osmolality and ions in its extracellular fluid. Osmotic and ionic changes in its watery environment represent a challenge for the tissues of this mollusk. Thus we evaluated, in vitro, muscle tissue volume variations (based on wet weight change) under anisosmotic salines, as well the possible regulatory mechanisms involved in the processes. This tissue did not exhibit complete volume regulation under anisosmotic saline solutions, but showed less variation than would be predicted by Van't Hoff's law, and tissue volume remained essentially stable throughout 90 min of exposure. To minimize tissue swelling in hyposmotic situations, C. fluminea muscle mobilizes organic osmolytes (ninhydrin positive substances) and inorganic ions (K+ and Cl− ). While under hyperosmotic stimulus, apparently only inorganic osmolytes (Na+ and Cl− ) are mobilized by the tissue. Our results indicate ionic accumulation by the Na+–K+–2Cl− cotransporter and the Na+/H+ coupled to Cl−/HCO3 − exchangers. Exposure of the muscle tissue to Ca2+-free anisosmotic saline did not result in a detectable inhibition of the mechanisms described above. The Ca2+ gradient that derives from the absence of this ion, even apparently enhances the regulatory mechanisms. These responses of this freshwater mollusk in hyperosmotic solutions, and the muscle tissue under anisosmotic ( hypo and hyperosmotic) saline solutions, have not been previously characterized in the manner and approach as reported here. Specifically, we analyze both organic and inorganic osmolytes mobilized under hyposmotic stress, and can infer the participation of Na+ and Cl− pathways stimulated by hyperosmotic stress. From the perspective gained in this study, tissue volume responses may be used as models for toxicological investigations. pt_BR
dc.language.iso eng pt_BR
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dc.subject Hyperosmoconformer pt_BR
dc.subject In vitro assay pt_BR
dc.subject Hyposmotic pt_BR
dc.subject Hyperosmotic pt_BR
dc.subject Ionic transporters pt_BR
dc.title Osmotic stress and muscle tissue volume response of a freshwater bivalve pt_BR
dc.type article pt_BR

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