Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium release
Autor(a) principal: | |
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Data de Publicação: | 1997 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Brazilian Journal of Medical and Biological Research |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997001100015 |
Resumo: | Outward current oscillations associated with transient membrane hyperpolarizations were induced in murine macrophage polykaryons by membrane depolarization in the absence of external Na+. Oscillations corresponded to a cyclic activation of Ca2+-dependent K+ currents (IKCa) probably correlated with variations in intracellular Ca2+ concentration. Addition of external Na+ (8 mM) immediately abolished the outward current oscillations, suggesting that the absence of the cation is necessary not only for their induction but also for their maintenance. Oscillations were completely blocked by nisoldipine. Ruthenium red and ryanodine reduced the number of outward current cycles in each episode, whereas quercetin prolonged the hyperpolarization 2- to 15-fold. Neither low molecular weight heparin nor the absence of a Na+ gradient across the membrane had any influence on oscillations. The evidence suggests that Ca2+ entry through a pathway sensitive to Ca2+ channel blockers is elicited by membrane depolarization in Na+-free medium and is essential to initiate oscillations, which are also dependent on the cyclic release of Ca2+ from intracellular Ca2+-sensitive stores; Ca2+ ATPase acts by reducing intracellular Ca2+, thus allowing slow deactivation of IKCa. Evidence is presented that neither a Na+/Ca2+ antiporter nor Ca2+ release from IP3-sensitive Ca2+ stores participate directly in the mechanism of oscillation |
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Brazilian Journal of Medical and Biological Research |
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Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium releasemacrophagemacrophage polykaryonCa2+-dependent K+ currentmembrane potential oscillationscalcium-induced calcium releaseCa2+ ATPaseOutward current oscillations associated with transient membrane hyperpolarizations were induced in murine macrophage polykaryons by membrane depolarization in the absence of external Na+. Oscillations corresponded to a cyclic activation of Ca2+-dependent K+ currents (IKCa) probably correlated with variations in intracellular Ca2+ concentration. Addition of external Na+ (8 mM) immediately abolished the outward current oscillations, suggesting that the absence of the cation is necessary not only for their induction but also for their maintenance. Oscillations were completely blocked by nisoldipine. Ruthenium red and ryanodine reduced the number of outward current cycles in each episode, whereas quercetin prolonged the hyperpolarization 2- to 15-fold. Neither low molecular weight heparin nor the absence of a Na+ gradient across the membrane had any influence on oscillations. The evidence suggests that Ca2+ entry through a pathway sensitive to Ca2+ channel blockers is elicited by membrane depolarization in Na+-free medium and is essential to initiate oscillations, which are also dependent on the cyclic release of Ca2+ from intracellular Ca2+-sensitive stores; Ca2+ ATPase acts by reducing intracellular Ca2+, thus allowing slow deactivation of IKCa. Evidence is presented that neither a Na+/Ca2+ antiporter nor Ca2+ release from IP3-sensitive Ca2+ stores participate directly in the mechanism of oscillationAssociação Brasileira de Divulgação Científica1997-11-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997001100015Brazilian Journal of Medical and Biological Research v.30 n.11 1997reponame:Brazilian Journal of Medical and Biological Researchinstname:Associação Brasileira de Divulgação Científica (ABDC)instacron:ABDC10.1590/S0100-879X1997001100015info:eu-repo/semantics/openAccessSaraiva,R.M.Masuda,M.O.Oliveira-Castro,G.M.eng1998-10-07T00:00:00Zoai:scielo:S0100-879X1997001100015Revistahttps://www.bjournal.org/https://old.scielo.br/oai/scielo-oai.phpbjournal@terra.com.br||bjournal@terra.com.br1414-431X0100-879Xopendoar:1998-10-07T00:00Brazilian Journal of Medical and Biological Research - Associação Brasileira de Divulgação Científica (ABDC)false |
dc.title.none.fl_str_mv |
Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium release |
title |
Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium release |
spellingShingle |
Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium release Saraiva,R.M. macrophage macrophage polykaryon Ca2+-dependent K+ current membrane potential oscillations calcium-induced calcium release Ca2+ ATPase |
title_short |
Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium release |
title_full |
Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium release |
title_fullStr |
Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium release |
title_full_unstemmed |
Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium release |
title_sort |
Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium release |
author |
Saraiva,R.M. |
author_facet |
Saraiva,R.M. Masuda,M.O. Oliveira-Castro,G.M. |
author_role |
author |
author2 |
Masuda,M.O. Oliveira-Castro,G.M. |
author2_role |
author author |
dc.contributor.author.fl_str_mv |
Saraiva,R.M. Masuda,M.O. Oliveira-Castro,G.M. |
dc.subject.por.fl_str_mv |
macrophage macrophage polykaryon Ca2+-dependent K+ current membrane potential oscillations calcium-induced calcium release Ca2+ ATPase |
topic |
macrophage macrophage polykaryon Ca2+-dependent K+ current membrane potential oscillations calcium-induced calcium release Ca2+ ATPase |
description |
Outward current oscillations associated with transient membrane hyperpolarizations were induced in murine macrophage polykaryons by membrane depolarization in the absence of external Na+. Oscillations corresponded to a cyclic activation of Ca2+-dependent K+ currents (IKCa) probably correlated with variations in intracellular Ca2+ concentration. Addition of external Na+ (8 mM) immediately abolished the outward current oscillations, suggesting that the absence of the cation is necessary not only for their induction but also for their maintenance. Oscillations were completely blocked by nisoldipine. Ruthenium red and ryanodine reduced the number of outward current cycles in each episode, whereas quercetin prolonged the hyperpolarization 2- to 15-fold. Neither low molecular weight heparin nor the absence of a Na+ gradient across the membrane had any influence on oscillations. The evidence suggests that Ca2+ entry through a pathway sensitive to Ca2+ channel blockers is elicited by membrane depolarization in Na+-free medium and is essential to initiate oscillations, which are also dependent on the cyclic release of Ca2+ from intracellular Ca2+-sensitive stores; Ca2+ ATPase acts by reducing intracellular Ca2+, thus allowing slow deactivation of IKCa. Evidence is presented that neither a Na+/Ca2+ antiporter nor Ca2+ release from IP3-sensitive Ca2+ stores participate directly in the mechanism of oscillation |
publishDate |
1997 |
dc.date.none.fl_str_mv |
1997-11-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997001100015 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997001100015 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0100-879X1997001100015 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Associação Brasileira de Divulgação Científica |
publisher.none.fl_str_mv |
Associação Brasileira de Divulgação Científica |
dc.source.none.fl_str_mv |
Brazilian Journal of Medical and Biological Research v.30 n.11 1997 reponame:Brazilian Journal of Medical and Biological Research instname:Associação Brasileira de Divulgação Científica (ABDC) instacron:ABDC |
instname_str |
Associação Brasileira de Divulgação Científica (ABDC) |
instacron_str |
ABDC |
institution |
ABDC |
reponame_str |
Brazilian Journal of Medical and Biological Research |
collection |
Brazilian Journal of Medical and Biological Research |
repository.name.fl_str_mv |
Brazilian Journal of Medical and Biological Research - Associação Brasileira de Divulgação Científica (ABDC) |
repository.mail.fl_str_mv |
bjournal@terra.com.br||bjournal@terra.com.br |
_version_ |
1754302928869392384 |