Chlorotetracycline As An Indicator Of The Interaction Of Calcium With Brain Membrane Fractions
Autor(a) principal: | |
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Data de Publicação: | 1978 |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10316/8346 https://doi.org/10.1111/j.1471-4159.1978.tb12410.x |
Resumo: | The fluorescence of chlorotetracycline (CTC) in the presence of synaptosomes isolated from sheep brain is selectively increased by Ca2+ under conditions in which Mg2+, Na+, K+, Li+ or choline have only a small effect. The monovalent cations release bound Ca2+ from synaptosomes, and this effect is reflected by a decrease in the CTC fluorescence. Under optimal conditions there is a near parallelism between Ca2+ and CTC binding to the synaptosomes membranes, and Li+ is the monovalent cation tested which interferes the most with the binding of both substances. These results obtained in a predominantly sucrose medium become less distinct when media simulating physiological composition are utilized, which limits the usefulness of the method. Brain mitochondria and myelin also bind Ca2+ and CTC. The ratio of the fluorescence signal (or CTC bound) to Ca2+ bound is highest of all for mitochondrial membranes, and the apparent fluorescence quantum yield of CTC is also the highest in these membranes, which suggests that the Ca2+ in these membranes is localized in a more apolar region than is the case for synaptosomes and myelin. |
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Chlorotetracycline As An Indicator Of The Interaction Of Calcium With Brain Membrane FractionsThe fluorescence of chlorotetracycline (CTC) in the presence of synaptosomes isolated from sheep brain is selectively increased by Ca2+ under conditions in which Mg2+, Na+, K+, Li+ or choline have only a small effect. The monovalent cations release bound Ca2+ from synaptosomes, and this effect is reflected by a decrease in the CTC fluorescence. Under optimal conditions there is a near parallelism between Ca2+ and CTC binding to the synaptosomes membranes, and Li+ is the monovalent cation tested which interferes the most with the binding of both substances. These results obtained in a predominantly sucrose medium become less distinct when media simulating physiological composition are utilized, which limits the usefulness of the method. Brain mitochondria and myelin also bind Ca2+ and CTC. The ratio of the fluorescence signal (or CTC bound) to Ca2+ bound is highest of all for mitochondrial membranes, and the apparent fluorescence quantum yield of CTC is also the highest in these membranes, which suggests that the Ca2+ in these membranes is localized in a more apolar region than is the case for synaptosomes and myelin.1978info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/8346http://hdl.handle.net/10316/8346https://doi.org/10.1111/j.1471-4159.1978.tb12410.xengJournal of Neurochemistry. 30:5 (1978) 1149-1155Carvalho, C. A. 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:RCAAP2020-05-29T09:41:57Zoai:estudogeral.uc.pt:10316/8346Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:55:40.511637Repositório 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 |
Chlorotetracycline As An Indicator Of The Interaction Of Calcium With Brain Membrane Fractions |
title |
Chlorotetracycline As An Indicator Of The Interaction Of Calcium With Brain Membrane Fractions |
spellingShingle |
Chlorotetracycline As An Indicator Of The Interaction Of Calcium With Brain Membrane Fractions Carvalho, C. A. M. |
title_short |
Chlorotetracycline As An Indicator Of The Interaction Of Calcium With Brain Membrane Fractions |
title_full |
Chlorotetracycline As An Indicator Of The Interaction Of Calcium With Brain Membrane Fractions |
title_fullStr |
Chlorotetracycline As An Indicator Of The Interaction Of Calcium With Brain Membrane Fractions |
title_full_unstemmed |
Chlorotetracycline As An Indicator Of The Interaction Of Calcium With Brain Membrane Fractions |
title_sort |
Chlorotetracycline As An Indicator Of The Interaction Of Calcium With Brain Membrane Fractions |
author |
Carvalho, C. A. M. |
author_facet |
Carvalho, C. A. M. |
author_role |
author |
dc.contributor.author.fl_str_mv |
Carvalho, C. A. M. |
description |
The fluorescence of chlorotetracycline (CTC) in the presence of synaptosomes isolated from sheep brain is selectively increased by Ca2+ under conditions in which Mg2+, Na+, K+, Li+ or choline have only a small effect. The monovalent cations release bound Ca2+ from synaptosomes, and this effect is reflected by a decrease in the CTC fluorescence. Under optimal conditions there is a near parallelism between Ca2+ and CTC binding to the synaptosomes membranes, and Li+ is the monovalent cation tested which interferes the most with the binding of both substances. These results obtained in a predominantly sucrose medium become less distinct when media simulating physiological composition are utilized, which limits the usefulness of the method. Brain mitochondria and myelin also bind Ca2+ and CTC. The ratio of the fluorescence signal (or CTC bound) to Ca2+ bound is highest of all for mitochondrial membranes, and the apparent fluorescence quantum yield of CTC is also the highest in these membranes, which suggests that the Ca2+ in these membranes is localized in a more apolar region than is the case for synaptosomes and myelin. |
publishDate |
1978 |
dc.date.none.fl_str_mv |
1978 |
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/10316/8346 http://hdl.handle.net/10316/8346 https://doi.org/10.1111/j.1471-4159.1978.tb12410.x |
url |
http://hdl.handle.net/10316/8346 https://doi.org/10.1111/j.1471-4159.1978.tb12410.x |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Journal of Neurochemistry. 30:5 (1978) 1149-1155 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.source.none.fl_str_mv |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
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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) |
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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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