Dextrorphan attenuates responses of spinothalamic tract cells in normal and nerve-injured monkeys

Susan M. Carlton, Huw Rees, Kelli Gondesen, William D. Willis

    Research output: Contribution to journalArticlepeer-review

    15 Scopus citations


    Spinal cord N-methyl-D-aspartate (NMDA) receptors play an important role in the transmission of acute and chronic pain. The present study investigated the ability of dextrorphan (DEX), a metabolite of dextromethorphan and a clinically safe NMDA antagonist, to attenuate the responses of nociceptive spinothalamic tract (STT) neurons in anesthetized monkeys. The STT cells were recorded extracellularly in the lumbosacral enlargement and were identified by antidromic activation from the ventral posterior lateral thalamic nucleus. DEX administered through a microdialysis fiber inserted into the dorsal horn inhibited the responses of STT cells in normal animals to noxious pinch and heat stimuli. In monkeys made neuropathic by tight ligation of the L7 or S1 spinal nerve, DEX significantly attenuated the responses of STT cells to noxious pinch and heat, as well as to innocuous brushing, pressure and von Frey filament stimuli. These findings strongly suggest that DEX should be considered a potentially useful therapeutic agent for the treatment of neuropathic pain in humans.

    Original languageEnglish (US)
    Pages (from-to)169-172
    Number of pages4
    JournalNeuroscience Letters
    Issue number3
    StatePublished - Jul 4 1997


    • Allodynia
    • Glutamate antagonist
    • Hyperalgesia
    • NMDA
    • Nociception
    • Peripheral neuropathy

    ASJC Scopus subject areas

    • General Neuroscience


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