GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats
Braz. j. med. biol. res
; 42(1): 114-121, Jan. 2009. ilus
Article
em En
| LILACS
| ID: lil-505427
Biblioteca responsável:
BR1.1
ABSTRACT
We investigated the involvement of GABAergic mechanisms of the central amygdaloid nucleus (CeA) in unanesthetized rats subjected to acute isotonic or hypertonic blood volume expansion (BVE). Male Wistar rats bearing cannulas unilaterally implanted in the CeA were treated with vehicle, muscimol (0.2 nmol/0.2 µL) or bicuculline (1.6 nmol/0.2 µL) in the CeA, followed by isotonic or hypertonic BVE (0.15 or 0.3 M NaCl, 2 mL/100 g body weight over 1 min). The vehicle-treated group showed an increase in sodium excretion, urinary volume, plasma oxytocin (OT), and atrial natriuretic peptide (ANP) levels compared to control rats. Muscimol reduced the effects of BVE on sodium excretion (isotonic 2.4 ± 0.3 vs vehicle 4.8 ± 0.2 and hypertonic 4.0 ± 0.7 vs vehicle 8.7 ± 0.6 µEq·100 g-1·40 min-1); urinary volume after hypertonic BVE (83.8 ± 10 vs vehicle 255.6 ± 16.5 µL·100 g-1·40 min-1); plasma OT levels (isotonic 15.3 ± 0.6 vs vehicle 19.3 ± 1 and hypertonic 26.5 ± 2.6 vs vehicle 48 ± 3 pg/mL), and ANP levels (isotonic 97 ± 12.8 vs vehicle 258.3 ± 28.1 and hypertonic 160 ± 14.6 vs vehicle 318 ± 16.3 pg/mL). Bicuculline reduced the effects of isotonic or hypertonic BVE on urinary volume and ANP levels compared to vehicle-treated rats. However, bicuculline enhanced the effects of hypertonic BVE on plasma OT levels. These data suggest that CeA GABAergic mechanisms are involved in the control of ANP and OT secretion, as well as in sodium and water excretion in response to isotonic or hypertonic blood volume expansion.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
LILACS
Assunto principal:
Bicuculina
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Volume Sanguíneo
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Antagonistas GABAérgicos
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Agonistas GABAérgicos
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Tonsila do Cerebelo
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Muscimol
Limite:
Animals
Idioma:
En
Revista:
Braz. j. med. biol. res
Assunto da revista:
BIOLOGIA
/
MEDICINA
Ano de publicação:
2009
Tipo de documento:
Article
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Congress and conference
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Project document
País de afiliação:
Brasil
País de publicação:
Brasil