Antinociception mediated by the periaqueductal gray is attenuated by orphanin FQ

Michael M. Morgan, Judith E. Grisel, Carolyn S. Robbins, David K. Grandy

    Research output: Contribution to journalArticlepeer-review

    101 Scopus citations


    Orphanin FQ or nociceptin (OFQ/N1-17) is a recently discovered peptide which, upon intracerebroventricular administration, reverses opioid- mediated analgesias. OFQ/N1-17 terminals are located in the periaqueductal gray (PAG), a structure known to be involved in pain modulation, suggesting that the functional anti-opioid effects of OFQ/N1- 17 are mediated by PAG neurons. To test this, subsequent microinjections of morphine or kainic acid and OFQ/N1-17 were made into the PAG of awake rats. Administration of OFQ/N1-17 attenuated the tail flick inhibition produced by both morphine and kainic acid microinjection. OFQ/N1-17 attenuation of antinociception produced by a neuroexcitant indicates that OFQ/N1-17 reverses opioid antinociception by inhibiting PAG output neurons.

    Original languageEnglish (US)
    Pages (from-to)3431-3434
    Number of pages4
    Issue number16
    StatePublished - Jan 1 1997


    • Analgesia
    • Anti-opioid peptide
    • Morphine
    • Nociceptin
    • Opioid
    • Pain modulation

    ASJC Scopus subject areas

    • Neuroscience(all)


    Dive into the research topics of 'Antinociception mediated by the periaqueductal gray is attenuated by orphanin FQ'. Together they form a unique fingerprint.

    Cite this