The antiallodynic and antihyperalgesic effects of neurotropin in mice with spinal nerve ligation.

Abstract

Although Neurotropin(R) (NTP) has been used clinically as an analgesic in Japan for many years, its effect on neuropathic pain in animal models has not been examined in detail. Its main effect has been indicated to be activation of the descending monoaminergic pain inhibitory systems. To study the effect of NTP on neuropathic pain, we subjected mice to spinal nerve ligation. NTP inhibited both tactile allodynia and mechanical and thermal hyperalgesia in a dose-dependent manner. When the effect of NTP was examined after depletion of monoamines in the spinal cord by intrathecal neurotoxins, the antiallodynic and antihyperalgesic effects were still observed after serotonergic denervation, but not after noradrenergic denervation. In addition, intracerebroventricular NTP increased withdrawal threshold and latency although intrathecal or local administration of NTP did not. These results suggest that the antiallodynic and antihyperalgesic effect of NTP on neuropathic pain induced by spinal nerve ligation is mediated principally through the action at supraspinal sites and through activation of spinal noradrenergic systems, possibly via the descending inhibitory pathway.

• Authors: Takahiro Suzuki, Yong Hua Li, Takashi Mashimo
• Journal: Anesthesia and analgesia (Anesth Analg) Vol. 101 Issue 3 Pg. 793-799 (Sep 2005) ISSN: 0003-2999 [Print] United States
• PMID: 16115993 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Analgesics
• Biogenic Monoamines
• Polysaccharides
• Serotonin Agents
• 5,7-Dihydroxytryptamine
• neurotropin
• Oxidopamine

Topics

• 5,7-Dihydroxytryptamine
• Analgesics (administration & dosage, therapeutic use)
• Animals
• Behavior, Animal (drug effects)
• Biogenic Monoamines (metabolism, physiology)
• Hot Temperature
• Hyperalgesia (drug therapy, metabolism)
• Injections, Intraventricular
• Injections, Spinal
• Ligation
• Male
• Mice
• Mice, Inbred C57BL
• Oxidopamine
• Pain (drug therapy, metabolism)
• Pain Measurement (drug effects)
• Physical Stimulation
• Polysaccharides (administration & dosage, therapeutic use)
• Serotonin Agents
• Spinal Nerves (injuries, metabolism, pathology)
• Sympathectomy, Chemical