The effects of nitrous oxide on the central endogenous pro-opiomelanocortin system in the rat

John R Zuniga, Shirley A. Joseph, Karl M. Knigge

Research output: Contribution to journalArticle

33 Scopus citations


The hypothesis that nitrous oxide stimulates the central pro-opiomelanocortin system in vivo was explored in this study. A concentration-dependent stimulation of central pro-opiomelanocortin neuropeptides was demonstrated after exposures to variable concentrations of nitrous oxide with oxygen. Rats exposed to 60% and 80% nitrous oxide with oxygen demonstrated an elevation of β-endorphin concentration along the neuraxis involved with analgesia; no similar effect was observed in α-MSH concentration, neither duration of exposure nor acclimation to the enclosed environment altered this stimulation. The discontinuation of nitrous oxide exposure resulted in the diminution of β-endorphin concentration to pre-exposure levels in 15-30 min. With an ACTH1-39 antisera, a semi-quantitative increase in opiocortin immunoreactivity after exposures to nitrous oxide was demonstrated. In conclusion, the increase in β-endorphin concentration and immunoreactive ACTH1-39 staining in the cells of origin, areas of fiber projection and terminal fields suggest that nitrous oxide stimulates the central pro-opiomelanocortin system in vivo in the rat.

Original languageEnglish (US)
Pages (from-to)57-65
Number of pages9
JournalBrain Research
Issue number1
StatePublished - Sep 8 1987



  • Adrenocorticotropic hormone
  • Medial basal hypothalamus
  • Nitrous oxide
  • Periaqueductal gray
  • α-Melanocyte stimulating hormone
  • β-Endorphin

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

Cite this