Hypo-osmotic stimulation of active Na+ transport in frog muscle: apparent upregulation of Na+ pumps
- Autores
- Venosa, Roque Alberto
- Año de publicación
- 1991
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- The purpose of this work was to determine if hypotonicity, in addition to the stimulation of active Na+ transport (Venosa, R.A., 1978, Biochim. Biophys. Acta 510:378-383), promoted changes in (i) active K+ influx, (ii) passive Na+ and K+ fluxes, and (iii) the number of 3H-ouabain binding sites. The results indicate that a reduction of external osmotic pressure (pi) to one-half of its normal value (pi = 0.5) produced the following effects: (i) an increase in active K+ influx on the order of 160%, (ii) a 20% reduction in Na+ influx and K+ permeability (PK), and (iii) a 40% increase in the apparent density of ouabain binding sites. These data suggest that the hypotonic stimulation of the Na+ pump is not caused by an increased leak of either Na+ (inward) or K+ (outward). It is unlikely that the stimulation of active Na+ extrusion and the rise in the apparent number of pump sites produced by hypotonicity were due to a reduction of the intracellular ionic strength. It appears that, at least in part, the stimulation of active Na+ transport takes place whenever muscles are transferred from one medium to another of lower tonicity even if neither one was hypotonic (for instance pi = 2 to pi = 1 transfer). Comparison of the present results with those previously reported indicate that in addition to the number of pump sites, the cycling rate of the pump is increased by hypotonicity. Active Na+ and K+ fluxes were not significantly altered by hypertonicity (pi = 2).
Facultad de Ciencias Médicas - Materia
-
Ciencias Médicas
sodium pump
density
hypotonicity
frog muscle - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- http://creativecommons.org/licenses/by/4.0/
- Repositorio
- Institución
- Universidad Nacional de La Plata
- OAI Identificador
- oai:sedici.unlp.edu.ar:10915/143654
Ver los metadatos del registro completo
id |
SEDICI_36254ac3f6c99a259c4c24dc3d62488b |
---|---|
oai_identifier_str |
oai:sedici.unlp.edu.ar:10915/143654 |
network_acronym_str |
SEDICI |
repository_id_str |
1329 |
network_name_str |
SEDICI (UNLP) |
spelling |
Hypo-osmotic stimulation of active Na+ transport in frog muscle: apparent upregulation of Na+ pumpsVenosa, Roque AlbertoCiencias Médicassodium pumpdensityhypotonicityfrog muscleThe purpose of this work was to determine if hypotonicity, in addition to the stimulation of active Na+ transport (Venosa, R.A., 1978, Biochim. Biophys. Acta 510:378-383), promoted changes in (i) active K+ influx, (ii) passive Na+ and K+ fluxes, and (iii) the number of 3H-ouabain binding sites. The results indicate that a reduction of external osmotic pressure (pi) to one-half of its normal value (pi = 0.5) produced the following effects: (i) an increase in active K+ influx on the order of 160%, (ii) a 20% reduction in Na+ influx and K+ permeability (PK), and (iii) a 40% increase in the apparent density of ouabain binding sites. These data suggest that the hypotonic stimulation of the Na+ pump is not caused by an increased leak of either Na+ (inward) or K+ (outward). It is unlikely that the stimulation of active Na+ extrusion and the rise in the apparent number of pump sites produced by hypotonicity were due to a reduction of the intracellular ionic strength. It appears that, at least in part, the stimulation of active Na+ transport takes place whenever muscles are transferred from one medium to another of lower tonicity even if neither one was hypotonic (for instance pi = 2 to pi = 1 transfer). Comparison of the present results with those previously reported indicate that in addition to the number of pump sites, the cycling rate of the pump is increased by hypotonicity. Active Na+ and K+ fluxes were not significantly altered by hypertonicity (pi = 2).Facultad de Ciencias Médicas1991info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf97-104http://sedici.unlp.edu.ar/handle/10915/143654enginfo:eu-repo/semantics/altIdentifier/issn/0022-2631info:eu-repo/semantics/altIdentifier/issn/1432-1424info:eu-repo/semantics/altIdentifier/doi/10.1007/bf01872392info:eu-repo/semantics/altIdentifier/pmid/2072389info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International (CC BY 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:32:01Zoai:sedici.unlp.edu.ar:10915/143654Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:32:02.196SEDICI (UNLP) - Universidad Nacional de La Platafalse |
dc.title.none.fl_str_mv |
Hypo-osmotic stimulation of active Na+ transport in frog muscle: apparent upregulation of Na+ pumps |
title |
Hypo-osmotic stimulation of active Na+ transport in frog muscle: apparent upregulation of Na+ pumps |
spellingShingle |
Hypo-osmotic stimulation of active Na+ transport in frog muscle: apparent upregulation of Na+ pumps Venosa, Roque Alberto Ciencias Médicas sodium pump density hypotonicity frog muscle |
title_short |
Hypo-osmotic stimulation of active Na+ transport in frog muscle: apparent upregulation of Na+ pumps |
title_full |
Hypo-osmotic stimulation of active Na+ transport in frog muscle: apparent upregulation of Na+ pumps |
title_fullStr |
Hypo-osmotic stimulation of active Na+ transport in frog muscle: apparent upregulation of Na+ pumps |
title_full_unstemmed |
Hypo-osmotic stimulation of active Na+ transport in frog muscle: apparent upregulation of Na+ pumps |
title_sort |
Hypo-osmotic stimulation of active Na+ transport in frog muscle: apparent upregulation of Na+ pumps |
dc.creator.none.fl_str_mv |
Venosa, Roque Alberto |
author |
Venosa, Roque Alberto |
author_facet |
Venosa, Roque Alberto |
author_role |
author |
dc.subject.none.fl_str_mv |
Ciencias Médicas sodium pump density hypotonicity frog muscle |
topic |
Ciencias Médicas sodium pump density hypotonicity frog muscle |
dc.description.none.fl_txt_mv |
The purpose of this work was to determine if hypotonicity, in addition to the stimulation of active Na+ transport (Venosa, R.A., 1978, Biochim. Biophys. Acta 510:378-383), promoted changes in (i) active K+ influx, (ii) passive Na+ and K+ fluxes, and (iii) the number of 3H-ouabain binding sites. The results indicate that a reduction of external osmotic pressure (pi) to one-half of its normal value (pi = 0.5) produced the following effects: (i) an increase in active K+ influx on the order of 160%, (ii) a 20% reduction in Na+ influx and K+ permeability (PK), and (iii) a 40% increase in the apparent density of ouabain binding sites. These data suggest that the hypotonic stimulation of the Na+ pump is not caused by an increased leak of either Na+ (inward) or K+ (outward). It is unlikely that the stimulation of active Na+ extrusion and the rise in the apparent number of pump sites produced by hypotonicity were due to a reduction of the intracellular ionic strength. It appears that, at least in part, the stimulation of active Na+ transport takes place whenever muscles are transferred from one medium to another of lower tonicity even if neither one was hypotonic (for instance pi = 2 to pi = 1 transfer). Comparison of the present results with those previously reported indicate that in addition to the number of pump sites, the cycling rate of the pump is increased by hypotonicity. Active Na+ and K+ fluxes were not significantly altered by hypertonicity (pi = 2). Facultad de Ciencias Médicas |
description |
The purpose of this work was to determine if hypotonicity, in addition to the stimulation of active Na+ transport (Venosa, R.A., 1978, Biochim. Biophys. Acta 510:378-383), promoted changes in (i) active K+ influx, (ii) passive Na+ and K+ fluxes, and (iii) the number of 3H-ouabain binding sites. The results indicate that a reduction of external osmotic pressure (pi) to one-half of its normal value (pi = 0.5) produced the following effects: (i) an increase in active K+ influx on the order of 160%, (ii) a 20% reduction in Na+ influx and K+ permeability (PK), and (iii) a 40% increase in the apparent density of ouabain binding sites. These data suggest that the hypotonic stimulation of the Na+ pump is not caused by an increased leak of either Na+ (inward) or K+ (outward). It is unlikely that the stimulation of active Na+ extrusion and the rise in the apparent number of pump sites produced by hypotonicity were due to a reduction of the intracellular ionic strength. It appears that, at least in part, the stimulation of active Na+ transport takes place whenever muscles are transferred from one medium to another of lower tonicity even if neither one was hypotonic (for instance pi = 2 to pi = 1 transfer). Comparison of the present results with those previously reported indicate that in addition to the number of pump sites, the cycling rate of the pump is increased by hypotonicity. Active Na+ and K+ fluxes were not significantly altered by hypertonicity (pi = 2). |
publishDate |
1991 |
dc.date.none.fl_str_mv |
1991 |
dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Articulo http://purl.org/coar/resource_type/c_6501 info:ar-repo/semantics/articulo |
format |
article |
status_str |
publishedVersion |
dc.identifier.none.fl_str_mv |
http://sedici.unlp.edu.ar/handle/10915/143654 |
url |
http://sedici.unlp.edu.ar/handle/10915/143654 |
dc.language.none.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
info:eu-repo/semantics/altIdentifier/issn/0022-2631 info:eu-repo/semantics/altIdentifier/issn/1432-1424 info:eu-repo/semantics/altIdentifier/doi/10.1007/bf01872392 info:eu-repo/semantics/altIdentifier/pmid/2072389 |
dc.rights.none.fl_str_mv |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International (CC BY 4.0) |
eu_rights_str_mv |
openAccess |
rights_invalid_str_mv |
http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International (CC BY 4.0) |
dc.format.none.fl_str_mv |
application/pdf 97-104 |
dc.source.none.fl_str_mv |
reponame:SEDICI (UNLP) instname:Universidad Nacional de La Plata instacron:UNLP |
reponame_str |
SEDICI (UNLP) |
collection |
SEDICI (UNLP) |
instname_str |
Universidad Nacional de La Plata |
instacron_str |
UNLP |
institution |
UNLP |
repository.name.fl_str_mv |
SEDICI (UNLP) - Universidad Nacional de La Plata |
repository.mail.fl_str_mv |
alira@sedici.unlp.edu.ar |
_version_ |
1844616199557611520 |
score |
13.070432 |