High concentrations of KCl release noradrenaline from noradrenergic neurons in the rat anococcygeus muscle

Detalhes bibliográficos
Autor(a) principal: Araujo,C.B.L.
Data de Publicação: 2003
Outros Autores: Bendhack,L.M.
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=S0100-879X2003000100013
Resumo: The aim of the present study was to investigate the effects of high concentrations of KCl in releasing noradrenaline from sympathetic nerves and its actions on postsynaptic alpha-adrenoceptors. We measured the isotonic contractions induced by KCl in the isolated rat anococcygeus muscle under different experimental conditions. The contractile responses induced by KCl were inhibited by alpha-adrenoceptor antagonists in 2.5 mM Ca2+ solution. Prazosin reduced the maximum effect from 100 to 53.9 ± 10.2% (P<0.05) while the pD2 values were not changed. The contractile responses induced by KCl were abolished by prazosin in Ca2+-free solution (P<0.05). Treatment of the rats with reserpine reduced the maximum effect induced by KCl as compared to the contractile responses induced by acetylcholine from 339.5 ± 157.8 to 167.3 ± 65.5% (P<0.05), and increased the pD2 from 1.57 ± 0.01 to 1.65 ± 0.006 (P<0.05), but abolished the inhibitory effect of prazosin (P<0.05). In contrast, L-NAME increased the contractile responses induced by 120 mM KCl by 6.2 ± 2.3% (P<0.05), indicating that KCl could stimulate the neurons that release nitric oxide, an inhibitory component of the contractile response induced by KCl. Our results indicate that high concentrations of KCl induce the release of noradrenaline from noradrenergic neurons, which interacts with alpha1-adrenoceptors in smooth muscle cells, producing a contractile response in 2.5 mM Ca2+ (100%) and in Ca2+-free solution, part of which is due to a direct effect of KCl on the rat anococcygeus muscle.
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spelling High concentrations of KCl release noradrenaline from noradrenergic neurons in the rat anococcygeus muscleNoradrenalineKClAnococcygeus musclealpha-AdrenoceptorsNoradrenergic neuronsThe aim of the present study was to investigate the effects of high concentrations of KCl in releasing noradrenaline from sympathetic nerves and its actions on postsynaptic alpha-adrenoceptors. We measured the isotonic contractions induced by KCl in the isolated rat anococcygeus muscle under different experimental conditions. The contractile responses induced by KCl were inhibited by alpha-adrenoceptor antagonists in 2.5 mM Ca2+ solution. Prazosin reduced the maximum effect from 100 to 53.9 ± 10.2% (P<0.05) while the pD2 values were not changed. The contractile responses induced by KCl were abolished by prazosin in Ca2+-free solution (P<0.05). Treatment of the rats with reserpine reduced the maximum effect induced by KCl as compared to the contractile responses induced by acetylcholine from 339.5 ± 157.8 to 167.3 ± 65.5% (P<0.05), and increased the pD2 from 1.57 ± 0.01 to 1.65 ± 0.006 (P<0.05), but abolished the inhibitory effect of prazosin (P<0.05). In contrast, L-NAME increased the contractile responses induced by 120 mM KCl by 6.2 ± 2.3% (P<0.05), indicating that KCl could stimulate the neurons that release nitric oxide, an inhibitory component of the contractile response induced by KCl. Our results indicate that high concentrations of KCl induce the release of noradrenaline from noradrenergic neurons, which interacts with alpha1-adrenoceptors in smooth muscle cells, producing a contractile response in 2.5 mM Ca2+ (100%) and in Ca2+-free solution, part of which is due to a direct effect of KCl on the rat anococcygeus muscle.Associação Brasileira de Divulgação Científica2003-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000100013Brazilian Journal of Medical and Biological Research v.36 n.1 2003reponame:Brazilian Journal of Medical and Biological Researchinstname:Associação Brasileira de Divulgação Científica (ABDC)instacron:ABDC10.1590/S0100-879X2003000100013info:eu-repo/semantics/openAccessAraujo,C.B.L.Bendhack,L.M.eng2003-01-13T00:00:00Zoai:scielo:S0100-879X2003000100013Revistahttps://www.bjournal.org/https://old.scielo.br/oai/scielo-oai.phpbjournal@terra.com.br||bjournal@terra.com.br1414-431X0100-879Xopendoar:2003-01-13T00:00Brazilian Journal of Medical and Biological Research - Associação Brasileira de Divulgação Científica (ABDC)false
dc.title.none.fl_str_mv High concentrations of KCl release noradrenaline from noradrenergic neurons in the rat anococcygeus muscle
title High concentrations of KCl release noradrenaline from noradrenergic neurons in the rat anococcygeus muscle
spellingShingle High concentrations of KCl release noradrenaline from noradrenergic neurons in the rat anococcygeus muscle
Araujo,C.B.L.
Noradrenaline
KCl
Anococcygeus muscle
alpha-Adrenoceptors
Noradrenergic neurons
title_short High concentrations of KCl release noradrenaline from noradrenergic neurons in the rat anococcygeus muscle
title_full High concentrations of KCl release noradrenaline from noradrenergic neurons in the rat anococcygeus muscle
title_fullStr High concentrations of KCl release noradrenaline from noradrenergic neurons in the rat anococcygeus muscle
title_full_unstemmed High concentrations of KCl release noradrenaline from noradrenergic neurons in the rat anococcygeus muscle
title_sort High concentrations of KCl release noradrenaline from noradrenergic neurons in the rat anococcygeus muscle
author Araujo,C.B.L.
author_facet Araujo,C.B.L.
Bendhack,L.M.
author_role author
author2 Bendhack,L.M.
author2_role author
dc.contributor.author.fl_str_mv Araujo,C.B.L.
Bendhack,L.M.
dc.subject.por.fl_str_mv Noradrenaline
KCl
Anococcygeus muscle
alpha-Adrenoceptors
Noradrenergic neurons
topic Noradrenaline
KCl
Anococcygeus muscle
alpha-Adrenoceptors
Noradrenergic neurons
description The aim of the present study was to investigate the effects of high concentrations of KCl in releasing noradrenaline from sympathetic nerves and its actions on postsynaptic alpha-adrenoceptors. We measured the isotonic contractions induced by KCl in the isolated rat anococcygeus muscle under different experimental conditions. The contractile responses induced by KCl were inhibited by alpha-adrenoceptor antagonists in 2.5 mM Ca2+ solution. Prazosin reduced the maximum effect from 100 to 53.9 ± 10.2% (P<0.05) while the pD2 values were not changed. The contractile responses induced by KCl were abolished by prazosin in Ca2+-free solution (P<0.05). Treatment of the rats with reserpine reduced the maximum effect induced by KCl as compared to the contractile responses induced by acetylcholine from 339.5 ± 157.8 to 167.3 ± 65.5% (P<0.05), and increased the pD2 from 1.57 ± 0.01 to 1.65 ± 0.006 (P<0.05), but abolished the inhibitory effect of prazosin (P<0.05). In contrast, L-NAME increased the contractile responses induced by 120 mM KCl by 6.2 ± 2.3% (P<0.05), indicating that KCl could stimulate the neurons that release nitric oxide, an inhibitory component of the contractile response induced by KCl. Our results indicate that high concentrations of KCl induce the release of noradrenaline from noradrenergic neurons, which interacts with alpha1-adrenoceptors in smooth muscle cells, producing a contractile response in 2.5 mM Ca2+ (100%) and in Ca2+-free solution, part of which is due to a direct effect of KCl on the rat anococcygeus muscle.
publishDate 2003
dc.date.none.fl_str_mv 2003-01-01
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
format article
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dc.identifier.uri.fl_str_mv http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000100013
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dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 10.1590/S0100-879X2003000100013
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.36 n.1 2003
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
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