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Role of Spinal Cord Endogenous Opioid Peptides in the Antinociceptive Effect of Hyperbaric Oxygen (HBO 2 )
Author(s) -
Heeman Jacqueline,
Zhang Yangmiao,
Shirachi Donald Y.,
Quock Raymond M.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.886.8
Subject(s) - nociception , dynorphin , spinal cord , pharmacology , opioid , dynorphin a , medicine , endogenous opioid , opioid peptide , endogeny , anesthesia , neuropathic pain , hyperalgesia , intrathecal , chemistry , receptor , psychiatry
Earlier research demonstrated that HBO 2 treatment produces antinociception in an animal model of acute pain (Chung et al., J. Pain 11:847, 2010). We have previously demonstrated that intracerebroventricular (i.c.v.) pretreatment with opioid antagonists can reduce the magnitude of HBO 2 –induced antinociception in mice. The purpose of this study was to examine the role of opioid mechanisms in the spinal cord in the acute antinociceptive effect of HBO 2 in mice. Male NIH Swiss Mice, 18–22 g, were exposed to HBO 2 (100% oxygen @ 3.5 ATA) and, after 5 min, responsiveness to HBO2‐induced antinociception was assessed using the acetic acid‐induced abdominal constriction test. Different groups of mice were pretreated by intrathecal (i.t.) injection with the following: normal rabbit serum (NRS); and rabbit antisera (AS) against the rat methionine‐enkephalin (ME), dynorphin 1–17 (DYN) and β‐endorphin (βEP). NRS did not produce significant antinociception in control mice. In animals pretreated with NRS (control), HBO 2 produced a 59% antinociceptive response. In mice pretreated with DYN AS, ME AS and βEP AS, HBO 2 produced 27%, 52% and 46% antinociceptive responses, respectively. In conclusion, the dramatic decrease in the antinociceptive effect in mice pretreated with DYN AS suggests that DYN is the primary endogenous opioid peptide in the spinal cord that mediates HBO 2 ‐induced antinociception. (This research was supported by NIH Grant AT‐007222, the Allen I. White Distinguished Professorship at Washington State University and an institutional Summer Undergraduate Research Fellowship (SURF) Program from ASPET).