The endogenous cannabinoid, anandamide, activates the hypothalamo- pituitary-adrenal axis in CB1 cannabinoid receptor knockout mice

Tibor Wenger, Catherine Ledent, Gérard Tramu

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Abstract

The purpose of this study was to investigate the effects of the endogenous cannabinoid arachidonoyl-ethanolamide, anandamide (AEA), on the activity of the hypothalamo-pituitary-adrenal (HPA) axis in cannabinoid receptor (CB 1 receptor) inactivated (KO) mice. A low dose (0.01 mg/kg i.p.) of AEA significantly increased plasma corticotropin (ACTH) and corticosterone concentrations in both wild-type (+/+) and in mutant (-/-) animals. In each case, hormone levels reached their peaks at 90 min after AEA administration. In a parallel experiment, AEA administration was preceded by the injection of SR 141716A (1.0 mg/kg), a selective and potent CB1 receptor antagonist, or of capsazepine (5.0 mg/kg), a potent vanilloid receptor of type 1 (VR1) antagonist. The latter drugs did not prevent the effects of AEA on the HPA axis. Using Fos protein immunohistochemistry, we observed that the parvocellular part of the hypothalamic paraventricular nucleus (PVN) was activated as early as 45 min after AEA injection and reached peak levels after 60 min in both +/+ and -/- mice. Furthermore, the CB1 and VR1 receptor antagonists did not block the effects of AEA on Fos immunoreactivity. The results strongly support the view that activation of the HPA axis produced by AEA possibly occurs via a currently unknown (CBx) cannabinoid receptor present in PVN.

Original languageEnglish
Pages (from-to)294-300
Number of pages7
JournalNeuroendocrinology
Volume78
Issue number6
DOIs
Publication statusPublished - Jan 1 2003

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Keywords

  • Adrenal steroids
  • Cannabinoid receptors
  • Cannabinoids
  • Corticotropin
  • Immunocytochemistry
  • Mouse
  • Paraventricular nucleus
  • Transgenes
  • Vanilloid receptors
  • c-fos

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Endocrine and Autonomic Systems
  • Cellular and Molecular Neuroscience

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