Increase of the intracellular Ca2+ concentration mediated by transport of glutamate into rat hippocampal synaptosomes: characterization of the activated voltage sensitive Ca2+ channels
Autor(a) principal: | |
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Data de Publicação: | 1998 |
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/10316/5472 https://doi.org/10.1016/S0197-0186(97)00048-X |
Resumo: | The changes in the intracellular free Ca2+ concentration, [Ca2+]i, mediated by glutamate and D-aspartate into rat hippocampal synaptosomes was studied. Glutamate increased the [Ca2+]i in a dose-dependent manner with an EC50 of 1.87 [mu]M and a maximal increase of 31.5±0.9 nM. We also observed that stimulation of the synaptosomes with 100 [mu]M [alpha]-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), 100 [mu]M kainate, or 100 [mu]M D-aspartate increased the synaptosomal [Ca2+]i. The effect of either of these non-NMDA receptor agonists and of D-aspartate was additive, suggesting the activation of two different components (the ionotropic non-NMDA receptors or the glutamate transporters). Stimulation of synaptosomes with 100 [mu]M glutamate increased the [Ca2+]i and prevented the effect of either non-NMDA receptor agonists and the effect of D-aspartate. We also observed that incubation of the synaptosomes with D-aspartate induced the Ca2+-independent release of glutamate, possibly through the reversal of the glutamate carrier. The aim of incubating the synaptosomes with D-aspartate was to avoid undesirable secondary activation of glutamate receptors. After incubating the synaptosomes with 100 [mu]M D-aspartate (10 min at 37°C), the subsequent stimulation with D-aspartate increased the [Ca2+]i due to glutamate transport. this increase in [Ca2+]i induced by 100 [mu]M D-aspartate was insensitive to 1 [mu]M nitrendipine, but was inhibited by about 50% by the presence of both 500 nM [omega]-CgTx GVIA and 100 nM [omega]-Aga IVA or by 500 nM [omega]-CgTx MVIIC. We clearly identified two different processes by which glutamate increased the [Ca2+]i in rat hippocampal synaptosomes: activation of non-NMDA receptors and activation of the glutamate transporters. We also characterized the voltage sensitive Ca2+ channels (VSCC) activated as a consequence of the glutamate transport, and determined that class B (N-type) and class A (P or Q-type) Ca2+ channels were responsible for about 50% of the signal. |
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Increase of the intracellular Ca2+ concentration mediated by transport of glutamate into rat hippocampal synaptosomes: characterization of the activated voltage sensitive Ca2+ channelsThe changes in the intracellular free Ca2+ concentration, [Ca2+]i, mediated by glutamate and D-aspartate into rat hippocampal synaptosomes was studied. Glutamate increased the [Ca2+]i in a dose-dependent manner with an EC50 of 1.87 [mu]M and a maximal increase of 31.5±0.9 nM. We also observed that stimulation of the synaptosomes with 100 [mu]M [alpha]-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), 100 [mu]M kainate, or 100 [mu]M D-aspartate increased the synaptosomal [Ca2+]i. The effect of either of these non-NMDA receptor agonists and of D-aspartate was additive, suggesting the activation of two different components (the ionotropic non-NMDA receptors or the glutamate transporters). Stimulation of synaptosomes with 100 [mu]M glutamate increased the [Ca2+]i and prevented the effect of either non-NMDA receptor agonists and the effect of D-aspartate. We also observed that incubation of the synaptosomes with D-aspartate induced the Ca2+-independent release of glutamate, possibly through the reversal of the glutamate carrier. The aim of incubating the synaptosomes with D-aspartate was to avoid undesirable secondary activation of glutamate receptors. After incubating the synaptosomes with 100 [mu]M D-aspartate (10 min at 37°C), the subsequent stimulation with D-aspartate increased the [Ca2+]i due to glutamate transport. this increase in [Ca2+]i induced by 100 [mu]M D-aspartate was insensitive to 1 [mu]M nitrendipine, but was inhibited by about 50% by the presence of both 500 nM [omega]-CgTx GVIA and 100 nM [omega]-Aga IVA or by 500 nM [omega]-CgTx MVIIC. We clearly identified two different processes by which glutamate increased the [Ca2+]i in rat hippocampal synaptosomes: activation of non-NMDA receptors and activation of the glutamate transporters. We also characterized the voltage sensitive Ca2+ channels (VSCC) activated as a consequence of the glutamate transport, and determined that class B (N-type) and class A (P or Q-type) Ca2+ channels were responsible for about 50% of the signal.http://www.sciencedirect.com/science/article/B6T0B-3TDPXHV-1W/1/c4f513cb79dab43fc097b11df729bf791998info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleaplication/PDFhttp://hdl.handle.net/10316/5472http://hdl.handle.net/10316/5472https://doi.org/10.1016/S0197-0186(97)00048-XengNeurochemistry International. 32:1 (1998) 7-16Malva, João O.Ambrósio, António F.Carvalho, Arsélio P.Carvalho, Caetana M.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:RCAAP2021-07-21T10:02:52Zoai:estudogeral.uc.pt:10316/5472Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:55:31.191264Repositório 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 |
Increase of the intracellular Ca2+ concentration mediated by transport of glutamate into rat hippocampal synaptosomes: characterization of the activated voltage sensitive Ca2+ channels |
title |
Increase of the intracellular Ca2+ concentration mediated by transport of glutamate into rat hippocampal synaptosomes: characterization of the activated voltage sensitive Ca2+ channels |
spellingShingle |
Increase of the intracellular Ca2+ concentration mediated by transport of glutamate into rat hippocampal synaptosomes: characterization of the activated voltage sensitive Ca2+ channels Malva, João O. |
title_short |
Increase of the intracellular Ca2+ concentration mediated by transport of glutamate into rat hippocampal synaptosomes: characterization of the activated voltage sensitive Ca2+ channels |
title_full |
Increase of the intracellular Ca2+ concentration mediated by transport of glutamate into rat hippocampal synaptosomes: characterization of the activated voltage sensitive Ca2+ channels |
title_fullStr |
Increase of the intracellular Ca2+ concentration mediated by transport of glutamate into rat hippocampal synaptosomes: characterization of the activated voltage sensitive Ca2+ channels |
title_full_unstemmed |
Increase of the intracellular Ca2+ concentration mediated by transport of glutamate into rat hippocampal synaptosomes: characterization of the activated voltage sensitive Ca2+ channels |
title_sort |
Increase of the intracellular Ca2+ concentration mediated by transport of glutamate into rat hippocampal synaptosomes: characterization of the activated voltage sensitive Ca2+ channels |
author |
Malva, João O. |
author_facet |
Malva, João O. Ambrósio, António F. Carvalho, Arsélio P. Carvalho, Caetana M. |
author_role |
author |
author2 |
Ambrósio, António F. Carvalho, Arsélio P. Carvalho, Caetana M. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Malva, João O. Ambrósio, António F. Carvalho, Arsélio P. Carvalho, Caetana M. |
description |
The changes in the intracellular free Ca2+ concentration, [Ca2+]i, mediated by glutamate and D-aspartate into rat hippocampal synaptosomes was studied. Glutamate increased the [Ca2+]i in a dose-dependent manner with an EC50 of 1.87 [mu]M and a maximal increase of 31.5±0.9 nM. We also observed that stimulation of the synaptosomes with 100 [mu]M [alpha]-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), 100 [mu]M kainate, or 100 [mu]M D-aspartate increased the synaptosomal [Ca2+]i. The effect of either of these non-NMDA receptor agonists and of D-aspartate was additive, suggesting the activation of two different components (the ionotropic non-NMDA receptors or the glutamate transporters). Stimulation of synaptosomes with 100 [mu]M glutamate increased the [Ca2+]i and prevented the effect of either non-NMDA receptor agonists and the effect of D-aspartate. We also observed that incubation of the synaptosomes with D-aspartate induced the Ca2+-independent release of glutamate, possibly through the reversal of the glutamate carrier. The aim of incubating the synaptosomes with D-aspartate was to avoid undesirable secondary activation of glutamate receptors. After incubating the synaptosomes with 100 [mu]M D-aspartate (10 min at 37°C), the subsequent stimulation with D-aspartate increased the [Ca2+]i due to glutamate transport. this increase in [Ca2+]i induced by 100 [mu]M D-aspartate was insensitive to 1 [mu]M nitrendipine, but was inhibited by about 50% by the presence of both 500 nM [omega]-CgTx GVIA and 100 nM [omega]-Aga IVA or by 500 nM [omega]-CgTx MVIIC. We clearly identified two different processes by which glutamate increased the [Ca2+]i in rat hippocampal synaptosomes: activation of non-NMDA receptors and activation of the glutamate transporters. We also characterized the voltage sensitive Ca2+ channels (VSCC) activated as a consequence of the glutamate transport, and determined that class B (N-type) and class A (P or Q-type) Ca2+ channels were responsible for about 50% of the signal. |
publishDate |
1998 |
dc.date.none.fl_str_mv |
1998 |
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/10316/5472 http://hdl.handle.net/10316/5472 https://doi.org/10.1016/S0197-0186(97)00048-X |
url |
http://hdl.handle.net/10316/5472 https://doi.org/10.1016/S0197-0186(97)00048-X |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Neurochemistry International. 32:1 (1998) 7-16 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
aplication/PDF |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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