Na+ ATPase activities in chela muscle of the euryhaline crab Neohelice granulata: Differential response to environmental salinity
The occurrence and characteristics of ouabain-insensitive Na+ ATPase activity and the response to environmental salinity of the coexistent Na+-K+ ATPase and ouabain-insensitive Na+ ATPase activities were studied in chela muscle of the euryhaline crab Neohelice (Chasmagnathus) granulata from Mar Chiq...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2009 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/160062 |
| Acceso en línea: | http://hdl.handle.net/11336/160062 |
| Access Level: | acceso abierto |
| Palabra clave: | CRABS MUSCLE NA+ ATPASES NEOHELICE GRANULATA OSMOIONOREGULATION https://purl.org/becyt/ford/1.6 https://purl.org/becyt/ford/1 |
| Sumario: | The occurrence and characteristics of ouabain-insensitive Na+ ATPase activity and the response to environmental salinity of the coexistent Na+-K+ ATPase and ouabain-insensitive Na+ ATPase activities were studied in chela muscle of the euryhaline crab Neohelice (Chasmagnathus) granulata from Mar Chiquita coastal lagoon (Buenos Aires Province, Argentina). Chela muscle exhibited two ouabain-insensitive Na+ ATPase activities (a furosemide-insensitive and a furosemide-sensitive activity). I50 for ouabain-insensitive, furosemide-sensitive Na+ ATPase activity was about 1.4 mM. Both ouabain-insensitive, furosemide-insensitive and furosemide-sensitive Na+ ATPase activities were weakly affected by pH and showed Michaelis-Menten kinetics (Km = 0.021 and 0.224 mM, respectively). These characteristics appeared to be quite different from those previously described for Na+-K+ ATPase activity in chela muscle of this crab. Na+-K+ ATPase and ouabain-insensitive, furosemide-sensitive Na+ ATPase activities appeared to be sensitive to environmental salinity. In crabs acclimated to low salinity (10‰), a salinity at which N. granulata exhibits a strong hyperregulatory capacity, Na+-K+ ATPase activity was higher (117 ± 26 nmol Pi min- 1 mg prot- 1) than in 35‰ salinity (23 ± 6 nmol Pi min- 1 mg prot- 1) (a salinity at which this crab is osmoionoconforming). On the contrary, ouabain-insensitive, furosemide-sensitive Na+ ATPase activity was higher in 35‰ salinity (108 ±15 nmol Pi min- 1 mg prot- 1) than in crabs acclimated to 10‰ salinity (36 ± 11 nmol Pi min- 1 mg prot- 1). Ouabain-insensitive, furosemide-insensitive Na+ ATPase activity was not affected by acclimation of crabs to low salinity. The response to low salinity suggests that Na+-K+ ATPase could be a component of muscle regulatory mechanisms at the biochemical level secondary to hyperregulation whereas ouabain-insensitive, furosemide-sensitive activity appeared to be predominant upon osmoconforming conditions. The possible differential functional roles of Na+-K+ ATPase and ouabain-insensitive Na+ ATPase activities in muscle are discussed. |
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