A Toxin Fraction (FTX) from the Funnel-Web Spider Poison Inhibits Dihydropyridine-Insensitive Ca2+ Channels Coupled to Catecholamine Release in Bovine Adrenal Chromaffin Cells
Autor(a) principal: | |
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Data de Publicação: | 1993 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10316/8331 https://doi.org/10.1111/j.1471-4159.1993.tb03236.x |
Resumo: | In adrenal chromaffin cells, depolarization-evoked Ca2+ influx and catecholamine release are partially blocked by blockers of L-type voltage-sensitive Ca2+ channels. We have now evaluated the sensitivity of the dihydropyridine-resistant components of Ca2+ influx and catecholamine release to a toxin fraction (FTX) from the funnel-web spider poison, which is known to block P-type channels in mammalian neurons. FTX (1:4,000 dilution, with respect to the original fraction) inhibited K+-depolarization-induced Ca2+ influx by 50%, as monitored with fura-2, whereas nitrendipine (0.120131 03BCM) and FTX (3:3), a synthetic FTX analogue (1 mM), blocked the [Ca2+]i transients by 35 and 30%, respectively. When tested together, FTX and nitrendipine reduced the [Ca2+]i transients by 70%. FTX or nitrendipine reduced adrenaline and noradrenaline release by 223C80 and 70%, respectively, but both substances together abolished the K+-evoked catecholamine release, as measured by HPLC. The 03C9-conotoxin GVIA (0.5 03BCM) was without effect on K+-stimulated 45Ca2+ uptake. Our results indicate that FTX blocks dihydropyridine- and 03C9-conotoxin-insensitive Ca2+ channels that, together with L-type voltage-sensitive Ca2+ channels, are coupled to catecholamine release. |
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A Toxin Fraction (FTX) from the Funnel-Web Spider Poison Inhibits Dihydropyridine-Insensitive Ca2+ Channels Coupled to Catecholamine Release in Bovine Adrenal Chromaffin CellsIn adrenal chromaffin cells, depolarization-evoked Ca2+ influx and catecholamine release are partially blocked by blockers of L-type voltage-sensitive Ca2+ channels. We have now evaluated the sensitivity of the dihydropyridine-resistant components of Ca2+ influx and catecholamine release to a toxin fraction (FTX) from the funnel-web spider poison, which is known to block P-type channels in mammalian neurons. FTX (1:4,000 dilution, with respect to the original fraction) inhibited K+-depolarization-induced Ca2+ influx by 50%, as monitored with fura-2, whereas nitrendipine (0.120131 03BCM) and FTX (3:3), a synthetic FTX analogue (1 mM), blocked the [Ca2+]i transients by 35 and 30%, respectively. When tested together, FTX and nitrendipine reduced the [Ca2+]i transients by 70%. FTX or nitrendipine reduced adrenaline and noradrenaline release by 223C80 and 70%, respectively, but both substances together abolished the K+-evoked catecholamine release, as measured by HPLC. The 03C9-conotoxin GVIA (0.5 03BCM) was without effect on K+-stimulated 45Ca2+ uptake. Our results indicate that FTX blocks dihydropyridine- and 03C9-conotoxin-insensitive Ca2+ channels that, together with L-type voltage-sensitive Ca2+ channels, are coupled to catecholamine release.1993info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/8331http://hdl.handle.net/10316/8331https://doi.org/10.1111/j.1471-4159.1993.tb03236.xengJournal of Neurochemistry. 60:3 (1993) 908-913Duarte, Carlos B.Rosário, Luís M.Sena, Cristina M.Carvalho, Arsélio P.info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2021-10-26T09:24:28Zoai:estudogeral.uc.pt:10316/8331Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:55:38.670796Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
A Toxin Fraction (FTX) from the Funnel-Web Spider Poison Inhibits Dihydropyridine-Insensitive Ca2+ Channels Coupled to Catecholamine Release in Bovine Adrenal Chromaffin Cells |
title |
A Toxin Fraction (FTX) from the Funnel-Web Spider Poison Inhibits Dihydropyridine-Insensitive Ca2+ Channels Coupled to Catecholamine Release in Bovine Adrenal Chromaffin Cells |
spellingShingle |
A Toxin Fraction (FTX) from the Funnel-Web Spider Poison Inhibits Dihydropyridine-Insensitive Ca2+ Channels Coupled to Catecholamine Release in Bovine Adrenal Chromaffin Cells Duarte, Carlos B. |
title_short |
A Toxin Fraction (FTX) from the Funnel-Web Spider Poison Inhibits Dihydropyridine-Insensitive Ca2+ Channels Coupled to Catecholamine Release in Bovine Adrenal Chromaffin Cells |
title_full |
A Toxin Fraction (FTX) from the Funnel-Web Spider Poison Inhibits Dihydropyridine-Insensitive Ca2+ Channels Coupled to Catecholamine Release in Bovine Adrenal Chromaffin Cells |
title_fullStr |
A Toxin Fraction (FTX) from the Funnel-Web Spider Poison Inhibits Dihydropyridine-Insensitive Ca2+ Channels Coupled to Catecholamine Release in Bovine Adrenal Chromaffin Cells |
title_full_unstemmed |
A Toxin Fraction (FTX) from the Funnel-Web Spider Poison Inhibits Dihydropyridine-Insensitive Ca2+ Channels Coupled to Catecholamine Release in Bovine Adrenal Chromaffin Cells |
title_sort |
A Toxin Fraction (FTX) from the Funnel-Web Spider Poison Inhibits Dihydropyridine-Insensitive Ca2+ Channels Coupled to Catecholamine Release in Bovine Adrenal Chromaffin Cells |
author |
Duarte, Carlos B. |
author_facet |
Duarte, Carlos B. Rosário, Luís M. Sena, Cristina M. Carvalho, Arsélio P. |
author_role |
author |
author2 |
Rosário, Luís M. Sena, Cristina M. Carvalho, Arsélio P. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Duarte, Carlos B. Rosário, Luís M. Sena, Cristina M. Carvalho, Arsélio P. |
description |
In adrenal chromaffin cells, depolarization-evoked Ca2+ influx and catecholamine release are partially blocked by blockers of L-type voltage-sensitive Ca2+ channels. We have now evaluated the sensitivity of the dihydropyridine-resistant components of Ca2+ influx and catecholamine release to a toxin fraction (FTX) from the funnel-web spider poison, which is known to block P-type channels in mammalian neurons. FTX (1:4,000 dilution, with respect to the original fraction) inhibited K+-depolarization-induced Ca2+ influx by 50%, as monitored with fura-2, whereas nitrendipine (0.120131 03BCM) and FTX (3:3), a synthetic FTX analogue (1 mM), blocked the [Ca2+]i transients by 35 and 30%, respectively. When tested together, FTX and nitrendipine reduced the [Ca2+]i transients by 70%. FTX or nitrendipine reduced adrenaline and noradrenaline release by 223C80 and 70%, respectively, but both substances together abolished the K+-evoked catecholamine release, as measured by HPLC. The 03C9-conotoxin GVIA (0.5 03BCM) was without effect on K+-stimulated 45Ca2+ uptake. Our results indicate that FTX blocks dihydropyridine- and 03C9-conotoxin-insensitive Ca2+ channels that, together with L-type voltage-sensitive Ca2+ channels, are coupled to catecholamine release. |
publishDate |
1993 |
dc.date.none.fl_str_mv |
1993 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10316/8331 http://hdl.handle.net/10316/8331 https://doi.org/10.1111/j.1471-4159.1993.tb03236.x |
url |
http://hdl.handle.net/10316/8331 https://doi.org/10.1111/j.1471-4159.1993.tb03236.x |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Journal of Neurochemistry. 60:3 (1993) 908-913 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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