TY - JOUR
T1 - Glutamate and GABA in the medial amygdala induce selective central sympathetic/ parasympathetic cardiovascular responses
AU - Neckel, Helinton
AU - Quagliotto, Edson
AU - Casali, Karina R.
AU - Montano, Nicola
AU - Lago, Pedro Dal
AU - Rasia-Filho, Alberto A.
PY - 2012/5
Y1 - 2012/5
N2 - 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.
AB - 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.
KW - Baroreceptor reflex
KW - Blood pressure
KW - Central cardiovascular control
KW - Chemoreceptor reflex
KW - Extended amygdala
KW - Heart rate
KW - Power spectral analysis
KW - Symbolic analysis
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U2 - 10.1139/Y2012-024
DO - 10.1139/Y2012-024
M3 - Article
C2 - 22512449
AN - SCOPUS:84860803944
VL - 90
SP - 525
EP - 536
JO - Canadian Journal of Physiology and Pharmacology
JF - Canadian Journal of Physiology and Pharmacology
SN - 0008-4212
IS - 5
ER -