Involvement of μ-opioid receptors in the modulation of pituitary-adrenal axis in normal and stressed rats

E. C. degli Uberti, F. Petraglia, M. Bondanelli, A. L. Guo, A. Valentini, S. Salvadori, M. Criscuolo, R. E. Nappi, A. R. Genazzani

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Abstract

The availability of the most selective, high-affinity, natural opioid agonists for μ-receptors (dermorphin-DM) and δ-receptors (deltorphin-DT) has provided the possibility for in vivo studying of the role of acute and chronic activation of μ-and δ-opioid receptors on the functional activity of the hypothalamus-pituitary-adrenocortical (HPA) axis, both in basal conditions and in response to an acute stress in adult male rats. Plasma corticosterone (CS) and ß-endorphin-like-immunoreactivity (ß-EP-LI) levels were measured by specific radioimmunoassays before and after 5 and 30 minutes from the exposure to cold (3±0.5 C) water and forcing them to swim for 10 minutes (acute cold swimming stress). Acute administration of DM, the specific μ-receptor agonist, enhanced basal and stress induced plasma levels of CS and ß-EP-LI. These effects were antagonized by pretreatment with nalox-one, specific μ-opioid receptor antagonist, but not by naltrindole, a δ-opioid receptor antagonist. Long-term administration of DM did not alter resting plasma levels of CS and ß-EP-LI, but significantly reduced stress-induced increase of these hormones. Both the acute and chronic administration of the DT, highly selective δ-opioid receptors agonist, failed to modify resting and stress induced hormone levels. Our present data show that DM throughout μ-opioid receptors, but not DT, modulates the response of HPA axis to acute stress in rats, increasing or decreasing the release of CS and ß-EP-LI when acutely or chronically administered, respectively.

Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalJournal of Endocrinological Investigation
Volume18
Issue number1
DOIs
Publication statusPublished - 1995

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Keywords

  • Corticosterone
  • deltorphin
  • dermorphin
  • ß-endorphin
  • stress
  • δ-receptors
  • μ-receptors

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

degli Uberti, E. C., Petraglia, F., Bondanelli, M., Guo, A. L., Valentini, A., Salvadori, S., Criscuolo, M., Nappi, R. E., & Genazzani, A. R. (1995). Involvement of μ-opioid receptors in the modulation of pituitary-adrenal axis in normal and stressed rats. Journal of Endocrinological Investigation, 18(1), 1-7. https://doi.org/10.1007/BF03349688