Synaptic plasticity in the substantia gelatinosa in a model of chronic neuropathic pain

Robby J. P. Jaken*, Elbert A. J. Joosten, Martin Knuwer, Rianne Miller, Inge van der Meulen, Marco A. E. Marcus, Ronald Deumens

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

16 Citations (Web of Science)

Abstract

Chronic neuropathic pain (CNP) is common after peripheral nerve injuries (PNI), but is rather refractory to available anti-pain medication. Advances in neuropathic pain research have identified cellular and molecular cues triggering the onset of neuropathic pain, but the mechanisms responsible for maintenance of chronic pain states are largely unknown. Structural changes such as sprouting of injured A-fibres into the substantia gelatinosa of the dorsal horn in the spinal cord have been proposed to relate to neuropathic pain in partial PNI models. Structural changes in central pain networks may also underlie the more persistent CNP following complete sectioning of a peripheral nerve, because this type of injury results in continuous and spontaneous afferent input to the spinal cord, which can trigger central sensitization. In the present study, the left sciatic nerve was completely sectioned and a 1-cm segment was removed to maintain a chronic pathology, whereas the right sciatic nerve was left intact. Mechanical allodyma was measured up to 84 days after injury, after which synaptic changes were studied in the lumbar substantia gelatinosa. The numbers of larger sized synaptophysin-immunoreactive presynaptic boutons were found to be increased in the substantia gelatinosa ipsilateral to the nerve injury. From these data we conclude that structural synaptic changes within the substantia gelatinosa are present months after complete nerve injury and that this plasticity may be involved in maintaining neuropathic pain states.
Original languageEnglish
Pages (from-to)30-33
JournalNeuroscience Letters
Volume469
Issue number1
DOIs
Publication statusPublished - 18 Jan 2010

Keywords

  • Allodynia
  • Plasticity
  • Synaptophysin
  • Rat
  • Sciatic nerve
  • Structural changes

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