The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA(A) receptors in the nucleus tractus solitarius of awake rats

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dc.contributor.authorCallera, Joao Carlos
dc.contributor.authorColombari, Eduardo [UNIFESP]
dc.contributor.authorDe Luca, Laurival Antonio
dc.contributor.authorMenani, Jose Vanderlei
dc.contributor.institutionUNESP
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.date.accessioned2016-01-24T12:37:58Z
dc.date.available2016-01-24T12:37:58Z
dc.date.issued2005-07-01
dc.description.abstractWe 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 mu g/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 GABAA 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.en
dc.description.affiliationUNESP, Fac Odontol, Dept Ciencias Basicas, BR-16015050 Aracatuba, SP, Brazil
dc.description.affiliationUNESP, Fac Odontol, Dept Fisiol & Patol, BR-16015050 Aracatuba, SP, Brazil
dc.description.affiliationUniversidade Federal de São Paulo, Escola Paulista Med, Dept Fisiol, São Paulo, Brazil
dc.description.affiliationUnifespUniversidade Federal de São Paulo, Escola Paulista Med, Dept Fisiol, São Paulo, Brazil
dc.description.sourceWeb of Science
dc.format.extent1123-1131
dc.identifierhttp://dx.doi.org/10.1590/S0100-879X2005000700016
dc.identifier.citationBrazilian Journal of Medical and Biological Research. São Paulo: Assoc Bras Divulg Cientifica, v. 38, n. 7, p. 1123-1131, 2005.
dc.identifier.doi10.1590/S0100-879X2005000700016
dc.identifier.issn0100-879X
dc.identifier.scieloS0100-879X2005000700016
dc.identifier.urihttp://repositorio.unifesp.br/handle/11600/28383
dc.identifier.wosWOS:000230829900016
dc.language.isoeng
dc.publisherAssoc Bras Divulg Cientifica
dc.relation.ispartofBrazilian Journal of Medical and Biological Research
dc.rightsinfo:eu-repo/semantics/openAccess
dc.subjectmuscimolen
dc.subjectGABA receptorsen
dc.subjectnucleus tractus solitariusen
dc.subjectparasympathetic componenten
dc.subjectBezold-Jarisch reflexen
dc.subjectawake ratsen
dc.titleThe bradycardic and hypotensive responses to serotonin are reduced by activation of GABA(A) receptors in the nucleus tractus solitarius of awake ratsen
dc.typeinfo:eu-repo/semantics/article
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