Abstract |
We hypothesized that neuropeptides released from the peripheral terminals of primary afferents play an important role in mechanical hyperalgesia after peripheral nerve injury. Nerve injury was performed on rats with lumbar 5 spinal nerve lesion (L5 SNL), which was preceded by L5 dorsal rhizotomy (L5 DR) to avoid the potential central effects induced by L5 SNL through the L5 dorsal root. L5 DR produced a short-lasting (<6 days) decrease in paw withdrawal threshold (PWT) while the following L5 SNL produced a persistent (>42 days) PWT decrease. When intraplantar injection to the affected hind paw was given immediately before L5 SNL, antagonists for both neurokinin 1 (NK1) and calcitonin gene-related peptide 1 (CGRP1) receptors delayed the onset of the PWT decrease for 2-4 days. However, when the same injection was given after L5 SNL, CGRP1, but not NK1, receptor antagonist reversed the decreased PWT for 105 min. It is suggested that peripherally released neuropeptides contribute to the generation of neuropathic pain, with substance P and CGRP contributing to its induction phase, but only CGRP to its maintenance phase.
|
Authors | Jun Ho Jang, Taick Sang Nam, Kwang Se Paik, Joong Woo Leem |
Journal | Neuroscience letters
(Neurosci Lett)
Vol. 360
Issue 3
Pg. 129-32
(Apr 29 2004)
ISSN: 0304-3940 [Print] Ireland |
PMID | 15082150
(Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
|
Chemical References |
- Peptide Fragments
- Piperidines
- calcitonin gene-related peptide (8-37)
- 3-((3,5-bis(trifluoromethyl)phenyl)methyloxy)-2-phenylpiperidine
- Substance P
- Calcitonin Gene-Related Peptide
|
Topics |
- Analysis of Variance
- Animals
- Calcitonin Gene-Related Peptide
(metabolism, pharmacology)
- Disease Models, Animal
- Functional Laterality
(physiology)
- Hyperalgesia
(etiology, metabolism)
- Lumbosacral Region
(injuries)
- Male
- Pain Measurement
(drug effects)
- Pain Threshold
(drug effects, physiology)
- Peptide Fragments
(pharmacology)
- Piperidines
(pharmacology)
- Rats
- Rats, Sprague-Dawley
- Rhizotomy
(methods)
- Spinal Cord Injuries
(complications)
- Statistics, Nonparametric
- Substance P
(metabolism)
- Time Factors
|