Antagonism of corticotrophin-releasing factor receptors in the fourth ventricle modifies responses to mild but not restraint stress

Joanna R. Miragaya, Ruth B.S. Harris

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Repeated restraint stress (RRS; 3 h of restraint on 3 consecutive days) in rodents produces temporary hypophagia, but a long-term downregulation of body weight. The mild stress (MS) of an intraperitoneal injection of saline and housing in a novel room for 2 h also inhibits food intake and weight gain, but the effects are smaller than for RRS. Previous exposure to RRS exaggerates hypophagia, glucocorticoid release, and anxiety-type behavior caused by MS. Here we tested the involvement of brain stem corticotrophin-releasing factor receptors (CRFR) in mediating energetic and glucocorticoid responses to RRS or MS and in promoting stress hyperresponsiveness in RRS rats. Administration of 1.3 nmol αhCRF(9-41), a nonspecific CRFR antagonist, exaggerated hypophagia and weight loss in both RRS and MS rats, whereas 0.26 nmol had no effect in RRS or MS rats. In contrast, 2 nmol of the nonspecific antagonist astressin had no effect on weight loss or hypersensitivity to subsequent MS in RRS rats, but blocked weight loss and inhibition of food intake caused by MS alone. MS rats infused with 3 nmol antisauvagine-30, a CRFR2 antagonist, did not lose weight in the 48 h after MS, but 0.3 nmol did not prevent weight loss in MS rats. These data suggest that inhibition of food intake and weight loss induced by RRS or by MS involve different pathways, with hindbrain CRFR mediating the effect of MS on body weight and food intake. Hindbrain CRFR do not appear to influence stressinduced corticosterone release in RRS rats.

Original languageEnglish (US)
Pages (from-to)R404-R416
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume295
Issue number2
DOIs
StatePublished - Aug 1 2008

Fingerprint

Corticotropin-Releasing Hormone Receptors
Fourth Ventricle
Weight Loss
Eating
Rhombencephalon
Glucocorticoids
Body Weight
Corticosterone
Intraperitoneal Injections
Brain Stem
Weight Gain
Rodentia
Hypersensitivity
Down-Regulation
Anxiety
Weights and Measures

Keywords

  • Antisauvagine-30
  • Astressin
  • Brain stem
  • Rats
  • αhCRF

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

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title = "Antagonism of corticotrophin-releasing factor receptors in the fourth ventricle modifies responses to mild but not restraint stress",
abstract = "Repeated restraint stress (RRS; 3 h of restraint on 3 consecutive days) in rodents produces temporary hypophagia, but a long-term downregulation of body weight. The mild stress (MS) of an intraperitoneal injection of saline and housing in a novel room for 2 h also inhibits food intake and weight gain, but the effects are smaller than for RRS. Previous exposure to RRS exaggerates hypophagia, glucocorticoid release, and anxiety-type behavior caused by MS. Here we tested the involvement of brain stem corticotrophin-releasing factor receptors (CRFR) in mediating energetic and glucocorticoid responses to RRS or MS and in promoting stress hyperresponsiveness in RRS rats. Administration of 1.3 nmol αhCRF(9-41), a nonspecific CRFR antagonist, exaggerated hypophagia and weight loss in both RRS and MS rats, whereas 0.26 nmol had no effect in RRS or MS rats. In contrast, 2 nmol of the nonspecific antagonist astressin had no effect on weight loss or hypersensitivity to subsequent MS in RRS rats, but blocked weight loss and inhibition of food intake caused by MS alone. MS rats infused with 3 nmol antisauvagine-30, a CRFR2 antagonist, did not lose weight in the 48 h after MS, but 0.3 nmol did not prevent weight loss in MS rats. These data suggest that inhibition of food intake and weight loss induced by RRS or by MS involve different pathways, with hindbrain CRFR mediating the effect of MS on body weight and food intake. Hindbrain CRFR do not appear to influence stressinduced corticosterone release in RRS rats.",
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