Glutamate and GABA in the medial amygdala induce selective central sympathetic/ parasympathetic cardiovascular responses

Helinton Neckel, Edson Quagliotto, Karina R. Casali, Nicola Montano, Pedro Dal Lago, Alberto A. Rasia-Filho

Research output: Contribution to journalArticle

Abstract

Glutamate and g-aminobutyric acid (GABA) participate in central cardiovascular control, and are found in the rat posterodorsal medial amygdala (MePD), an area of the forebrain that modulates emotional/social behaviors. Here we tested whether these neurotransmitters in the MePD could change the basal activity, chemoreflex, and baroreflex cardiovascular responses in awake rats. Power spectral analysis and symbolic analysis were used to evaluate these responses. Microinjections of saline, glutamate (2 μg), or GABA (61 ng or 100 μg; n = 5-7 rats per group) did not affect basal parameters or chemoreflex responses. However, baroreflex responses showed marked changes. Glutamate increased power spectral and symbolic sympathetic indexes related to both cardiac and vascular modulations (P <0.05). In turn, the displacement of the baroreflex half-maximal heart rate (HR) response was associated with a GABA (61 ng) mediated decrease in the upper plateau (P <0.05). Administration of GABA (61 ng, but not 100 μg) also increased HR variability (P <0.05), in association with parasympathetic activation. These data add novel evidence that the MePD can promote selective responses in the central regulation of the cardiovascular system, i.e., glutamate in the MePD evoked activation of a central sympathetic reflex adjustment, whereas GABA activated a central parasympathetic one.

Original languageEnglish
Pages (from-to)525-536
Number of pages12
JournalCanadian Journal of Physiology and Pharmacology
Volume90
Issue number5
DOIs
Publication statusPublished - May 2012

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Keywords

  • Baroreceptor reflex
  • Blood pressure
  • Central cardiovascular control
  • Chemoreceptor reflex
  • Extended amygdala
  • Heart rate
  • Power spectral analysis
  • Symbolic analysis

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Pharmacology

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