Glutamate and GABA in the medial amygdala induce selective central sympathetic/parasympathetic cardiovascular responses.
Can J Physiol Pharmacol
; 90(5): 525-36, 2012 May.
Article
em En
| MEDLINE
| ID: mdl-22512449
ABSTRACT
Glutamate and γ-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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sistema Nervoso Simpático
/
Sistema Cardiovascular
/
Ácido Glutâmico
/
Ácido gama-Aminobutírico
/
Tonsila do Cerebelo
Limite:
Animals
Idioma:
En
Revista:
Can J Physiol Pharmacol
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Brasil