Intraplantar injection of dextrorphan, ketamine or memantine attenuates formalin-induced behaviors

Elyad M. Davidson, Susan M. Carlton

    Research output: Contribution to journalArticlepeer-review

    127 Scopus citations


    The possible prophylactic effects of local injection of NMDA receptor antagonists that are currently used in humans was investigated in the present study. Intraplantar pretreatment with either 5 mM dextrorphan (DEX), 10 mM memantine (MEM) or 10 mM ketamine (KET) significantly attenuated formalin- induced lifting and licking behaviors, however flinching behavior was not effected. Control experiments indicated that these drug actions could be attributed to local and not systemic effects of the antagonists. We hypothesize that these actions result from blocking NMDA receptors present on unmyelinated sensory axons in the skin. These data suggest that peripheral NMDA receptors contribute to nociceptor activation and can be manipulated to reduce pain of peripheral origin. Since DEX, MEM and KET are currently used in humans and considered clinically safe, they have potential therapeutic value in the treatment of physiologic or pathologic pain states which are induced or maintained by peripheral nociceptor activity. Topical or local application would avoid the side effects that can accompany systemic or intrathecal injection of NMDA antagonists.

    Original languageEnglish (US)
    Pages (from-to)136-142
    Number of pages7
    JournalBrain Research
    Issue number1
    StatePublished - Feb 23 1998


    • Glutamate antagonist
    • NMDA
    • Nociception
    • Spontaneous pain

    ASJC Scopus subject areas

    • Neuroscience(all)


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