Effect of vasopressin 1b receptor blockade on the hypothalamic-pituitary-adrenal response of chronically stressed rats to a heterotypic stressor.
J Endocrinol
; 200(3): 285-91, 2009 Mar.
Article
em En
| MEDLINE
| ID: mdl-19074473
ABSTRACT
Exposure to chronic restraint (CR) modifies the hypothalamic-pituitary-adrenal (HPA) axis response to subsequent acute stressors with adaptation of the response to a homotypic and sensitization of the response to a heterotypic stressor. Since vasopressin (AVP) activity has been reported to change during chronic stress, we investigated whether this was an important factor in HPA facilitation. We therefore tested whether vasopressin 1b receptor (AVPR1B) blockade altered the ACTH and corticosterone response to heterotypic stressors following CR stress. Adult male rats were exposed to CR, single restraint, or were left undisturbed in the home cage. Twenty-four hours after the last restraint, rats were injected with either a AVPR1B antagonist (Org, 30 mg/kg, s.c.) or vehicle (5% mulgofen in saline, 0.2/kg, s.c.) and then exposed to either restraint, lipopolysaccharide (LPS) or white noise. CR resulted in the adaptation of the ACTH and corticosterone response to restraint and this effect was not prevented by pretreatment with Org. Although we found no effect of CR on LPS-induced ACTH and corticosterone secretion, both repeated and single episodes of restraint induced the sensitization of the ACTH, but not corticosterone response to acute noise. Pretreatment with Org reduced the exaggerated ACTH response to noise after both single and repeated exposure to restraint.
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Base de dados:
MEDLINE
Assunto principal:
Sistema Hipófise-Suprarrenal
/
Restrição Física
/
Antagonistas dos Receptores de Hormônios Antidiuréticos
/
Sistema Hipotálamo-Hipofisário
Limite:
Animals
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article