GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats
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.
Main Authors: | Margatho,L.O., Elias,L.L.K., Antunes-Rodrigues,J. |
---|---|
Format: | Digital revista |
Language: | English |
Published: |
Associação Brasileira de Divulgação Científica
2009
|
Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000100016 |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Similar Items
-
The effect of 5-HT2a/2c receptor agonist microinjected into central amygdaloid nucleus and median preoptic area on maternal aggressive behavior in rats
by: Almeida,Rosa Maria Martins de, et al.
Published: (2006) -
The bradycardic and hypotensive responses to serotonin are reduced by activation of GABA A receptors in the nucleus tractus solitarius of awake rats
by: Callera,J.C., et al.
Published: (2005) -
Antinociception induced by stimulating amygdaloid nuclei in rats: changes produced by systemically administered antagonists
by: Oliveira,M.A., et al.
Published: (1998) -
Enhancement of basolateral amygdaloid neuronal dendritic arborization following Bacopa monniera extract treatment in adult rats
by: Vollala,Venkata Ramana, et al.
Published: (2011) -
The compulsive-like aspect of the head dipping emission in rats with chronic electrolytic lesion in the area of the median raphe nucleus
by: Hoshino,K., et al.
Published: (2004)