Molecular Neurobiology

, Volume 25, Issue 2, pp 167–189

Neurobiology of nitrous oxide-induced antinociceptive effects


DOI: 10.1385/MN:25:2:167

Cite this article as:
Fujinaga, M. & Maze, M. Mol Neurobiol (2002) 25: 167. doi:10.1385/MN:25:2:167


Nitrous oxide (N2O), or laughing gas, has been used for clinical anesthesia for more than a century and is still commonly used. While the anesthetic/hypnotic mechanisms of N2O remain largely unknown, the underlying mechanisms of its analgesic/antinociceptive effects have been elucidated during the last several decades. Evidence to date indicate that N2O induces opioid peptide release in the periaqueductal gray area of the midbrain leading to the activation of the descending inhibitory pathways, which results in modulation of the pain/nociceptive processing in the spinal cord. The types of opioid peptide induced by N2O and the subtypes of opioid receptors that mediate the antinociceptive effects of N2O appear to depend on various factors including the species and/or strain, the regions of the brain, and the paradigms of behavior testing used for the experiments. Among three types of descending inhibitory pathways, the descending noradrenergic inhibitory pathway seems to play the most prominent role. The specific elements involved are now being resolved.

Index Entries

Nitrous oxide analgesia antinociceptive effect descending inhibitory pathway opioid peptides adrenoceptor GABA 

Copyright information

© Humana Press Inc 2002

Authors and Affiliations

  1. 1.Magill Department of AnaesthesiaIntensive Care and Pain Management Chelsea and Westminster HospitalLondonUK
  2. 2.Department of Anaesthetics and Intensive Care Imperial College of Science, Technology and MedicineUniversity of LondonLondonUK

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