ノイロトロピンによるセロトニン下行性疼痛抑制系の賦活化と鎮痛作用

• 岡井 恒

  九州大学大学院医学研究院 統合生理学 日本臓器製薬株式会社 生物活性科学研究所

• 古江 秀昌

  九州大学大学院医学研究院 統合生理学

• 吉村 恵

  九州大学大学院医学研究院 統合生理学

書誌事項

タイトル別名

• <b>Electrophysiological evidence for the involvement of facilitation of descending pain inhibitory system in the antinociceptive action of neurotropin </b>
• Electrophysiological evidence for the involvement of facilitation of descending pain inhibitory system in the antinociceptive action of neurotropin (in Japanese with abstract in English)

抄録

   Neurotropin^®, a non protein extract from inflamed rabbit skin inoculated with vaccinia virus, is well known as an analgesic for chronic pain such as low back pain and postherpetic neuralgia, etc. In previous behavioral studies, we have shown that neurotropin activates the monoaminergic descending pain inhibitory system. In the present study, we examined the effects of neurotropin on serotonergic neurons in the nucleus raphe magnus (NRM, the origin of serotonergic descending pain inhibitory neuron) in the rostroventromedial medulla using whole-cell patch-clamp technique in brainstem slices. In some instances, recorded neurons were identified as NRM neurons with neurobiotin filled in the recording pipettes. NRM neurons had a resting membrane potential of about -60 mV. Bath application of neurotropin (1.0 NU/mL) depolarized NRM neurons, and it resulted in initiating an action potential under current-clamp conditions. Under voltage-clamp conditions at a holding potential of -70 mV, NRM neurons exhibited spontaneous excitatory postsynaptic currents (EPSCs). Neurotropin (0.2 - 1.0 NU/mL) did not change the frequency and amplitude of spontaneous EPSCs. However, neurotropin dose-dependently induced an inward current in approximately 60% of NRM neurons tested. The neurotropin-induced inward current was observed even in the presence of tetrodotoxin (1 µM). The reversal potential for the current was close to 0 mV, indicating that the neurotropin-induced current is mediated by the activation of non-selective cation channels. Neurotropin produced an inward current, in all neurons immunohistochemically stained for tryptophan hydroxylase (TPH), a marker for serotonergic neuron. These results indicate that neurotropin directly excites serotonergic NRM neurons without affecting the excitatory synaptic inputs to NRM neurons. This facilitatory action of neurotropin on serotonergic NRM neurons may have an important role for the neurotropin-induced analgesia.

収録刊行物

• PAIN RESEARCH

  PAIN RESEARCH 23 (1), 11-18, 2008

  日本疼痛学会

キーワード

• Neurotropin
• Serotonin
• Analgesia
• Descending pain inhibitory system
• Postherpetic neuralgia

詳細情報

• CRID: 1390282679343634816
• NII論文ID: 10024130694
• NII書誌ID: AN10195934
• DOI: 10.11154/pain.23.11
• ISSN: 21874697
• ISSN: 09158588
• Web Site: https://www.jstage.jst.go.jp/article/pain/23/1/23_2/_pdf
• Web Site: https://search.jamas.or.jp/link/ui/2008150545
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• 抄録ライセンスフラグ: 使用不可