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

dc.contributorUniversidade Estadual Paulista (UNESP)
dc.creatorCallera, J. C.
dc.creatorColombari, Eduardo
dc.creatorDe Luca Jr., L.A.
dc.creatorMenani, José Vanderlei
dc.date2014-05-20T13:45:52Z
dc.date2014-05-20T13:45:52Z
dc.date2005-07-01
dc.date.accessioned2017-04-05T20:53:45Z
dc.date.available2017-04-05T20:53:45Z
dc.identifierBrazilian Journal of Medical and Biological Research. Associação Brasileira de Divulgação Científica, v. 38, n. 7, p. 1123-1131, 2005.
dc.identifier0100-879X
dc.identifierhttp://hdl.handle.net/11449/16179
dc.identifier10.1590/S0100-879X2005000700016
dc.identifierS0100-879X2005000700016
dc.identifierS0100-879X2005000700016.pdf
dc.identifierhttp://dx.doi.org/10.1590/S0100-879X2005000700016
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/863051
dc.descriptionWe 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.
dc.languageeng
dc.publisherAssociação Brasileira de Divulgação Científica (ABRADIC)
dc.relationBrazilian Journal of Medical and Biological Research
dc.rightsinfo:eu-repo/semantics/openAccess
dc.subjectMuscimol
dc.subjectGABA receptors
dc.subjectNucleus tractus solitarius
dc.subjectParasympathetic component
dc.subjectBezold-Jarisch reflex
dc.subjectAwake rats
dc.titleThe bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats
dc.typeOtro


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