The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats
Autor(a) principal: | |
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Data de Publicação: | 2005 |
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=S0100-879X2005000700016 |
Resumo: | We investigated the effects of bilateral injections of the GABA receptor agonists muscimol (GABA A) and baclofen (GABA B) into the nucleus tractus solitarius (NTS) on the bradycardia and hypotension induced by iv serotonin injections (5-HT, 2 µg/rat) in awake male Holtzman rats. 5-HT was injected in rats with stainless steel cannulas implanted bilaterally in the NTS, before and 5, 15, and 60 min after bilateral injections of muscimol or baclofen into the NTS. The responses to 5-HT were tested before and after the injection of atropine methyl bromide. Muscimol (50 pmol/50 nl, N = 8) into the NTS increased basal mean arterial pressure (MAP) from 115 ± 4 to 144 ± 6 mmHg, did not change basal heart rate (HR) and reduced the bradycardia (-40 ± 14 and -73 ± 26 bpm at 5 and 15 min, respectively, vs -180 ± 20 bpm for the control) and hypotension (-11 ± 4 and -14 ± 4 mmHg, vs -40 ± 9 mmHg for the control) elicited by 5-HT. Baclofen (12.5 pmol/50 nl, N = 7) into the NTS also increased basal MAP, but did not change basal HR, bradycardia or hypotension in response to 5-HT injections. Atropine methyl bromide (1 mg/kg body weight) injected iv reduced the bradycardic and hypotensive responses to 5-HT injections. The stimulation of GABA A receptors in the NTS of awake rats elicits a significant increase in basal MAP and decreases the cardiac Bezold-Jarisch reflex responses to iv 5-HT injections. |
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Brazilian Journal of Medical and Biological Research |
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The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake ratsMuscimolGABA receptorsNucleus tractus solitariusParasympathetic componentBezold-Jarisch reflexAwake ratsWe investigated the effects of bilateral injections of the GABA receptor agonists muscimol (GABA A) and baclofen (GABA B) into the nucleus tractus solitarius (NTS) on the bradycardia and hypotension induced by iv serotonin injections (5-HT, 2 µg/rat) in awake male Holtzman rats. 5-HT was injected in rats with stainless steel cannulas implanted bilaterally in the NTS, before and 5, 15, and 60 min after bilateral injections of muscimol or baclofen into the NTS. The responses to 5-HT were tested before and after the injection of atropine methyl bromide. Muscimol (50 pmol/50 nl, N = 8) into the NTS increased basal mean arterial pressure (MAP) from 115 ± 4 to 144 ± 6 mmHg, did not change basal heart rate (HR) and reduced the bradycardia (-40 ± 14 and -73 ± 26 bpm at 5 and 15 min, respectively, vs -180 ± 20 bpm for the control) and hypotension (-11 ± 4 and -14 ± 4 mmHg, vs -40 ± 9 mmHg for the control) elicited by 5-HT. Baclofen (12.5 pmol/50 nl, N = 7) into the NTS also increased basal MAP, but did not change basal HR, bradycardia or hypotension in response to 5-HT injections. Atropine methyl bromide (1 mg/kg body weight) injected iv reduced the bradycardic and hypotensive responses to 5-HT injections. The stimulation of GABA A receptors in the NTS of awake rats elicits a significant increase in basal MAP and decreases the cardiac Bezold-Jarisch reflex responses to iv 5-HT injections.Associação Brasileira de Divulgação Científica2005-07-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000700016Brazilian Journal of Medical and Biological Research v.38 n.7 2005reponame:Brazilian Journal of Medical and Biological Researchinstname:Associação Brasileira de Divulgação Científica (ABDC)instacron:ABDC10.1590/S0100-879X2005000700016info:eu-repo/semantics/openAccessCallera,J.C.Colombari,E.De Luca Jr.,L.A.Menani,J.V.eng2005-07-04T00:00:00Zoai:scielo:S0100-879X2005000700016Revistahttps://www.bjournal.org/https://old.scielo.br/oai/scielo-oai.phpbjournal@terra.com.br||bjournal@terra.com.br1414-431X0100-879Xopendoar:2005-07-04T00:00Brazilian Journal of Medical and Biological Research - Associação Brasileira de Divulgação Científica (ABDC)false |
dc.title.none.fl_str_mv |
The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats |
title |
The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats |
spellingShingle |
The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats Callera,J.C. Muscimol GABA receptors Nucleus tractus solitarius Parasympathetic component Bezold-Jarisch reflex Awake rats |
title_short |
The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats |
title_full |
The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats |
title_fullStr |
The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats |
title_full_unstemmed |
The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats |
title_sort |
The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats |
author |
Callera,J.C. |
author_facet |
Callera,J.C. Colombari,E. De Luca Jr.,L.A. Menani,J.V. |
author_role |
author |
author2 |
Colombari,E. De Luca Jr.,L.A. Menani,J.V. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Callera,J.C. Colombari,E. De Luca Jr.,L.A. Menani,J.V. |
dc.subject.por.fl_str_mv |
Muscimol GABA receptors Nucleus tractus solitarius Parasympathetic component Bezold-Jarisch reflex Awake rats |
topic |
Muscimol GABA receptors Nucleus tractus solitarius Parasympathetic component Bezold-Jarisch reflex Awake rats |
description |
We investigated the effects of bilateral injections of the GABA receptor agonists muscimol (GABA A) and baclofen (GABA B) into the nucleus tractus solitarius (NTS) on the bradycardia and hypotension induced by iv serotonin injections (5-HT, 2 µg/rat) in awake male Holtzman rats. 5-HT was injected in rats with stainless steel cannulas implanted bilaterally in the NTS, before and 5, 15, and 60 min after bilateral injections of muscimol or baclofen into the NTS. The responses to 5-HT were tested before and after the injection of atropine methyl bromide. Muscimol (50 pmol/50 nl, N = 8) into the NTS increased basal mean arterial pressure (MAP) from 115 ± 4 to 144 ± 6 mmHg, did not change basal heart rate (HR) and reduced the bradycardia (-40 ± 14 and -73 ± 26 bpm at 5 and 15 min, respectively, vs -180 ± 20 bpm for the control) and hypotension (-11 ± 4 and -14 ± 4 mmHg, vs -40 ± 9 mmHg for the control) elicited by 5-HT. Baclofen (12.5 pmol/50 nl, N = 7) into the NTS also increased basal MAP, but did not change basal HR, bradycardia or hypotension in response to 5-HT injections. Atropine methyl bromide (1 mg/kg body weight) injected iv reduced the bradycardic and hypotensive responses to 5-HT injections. The stimulation of GABA A receptors in the NTS of awake rats elicits a significant increase in basal MAP and decreases the cardiac Bezold-Jarisch reflex responses to iv 5-HT injections. |
publishDate |
2005 |
dc.date.none.fl_str_mv |
2005-07-01 |
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=S0100-879X2005000700016 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000700016 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0100-879X2005000700016 |
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.38 n.7 2005 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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1754302933884731392 |