Loss of spinal mu-opioid receptor is associated with mechanical allodynia in a rat model of peripheral neuropathy
- Authors
- Back, Seung Keun; Lee, Jaehee; Hong, Seung Kil; Na, Heung Sik
- Issue Date
- Jul-2006
- Publisher
- LIPPINCOTT WILLIAMS & WILKINS
- Keywords
- neuropathic pain; mechanical allodynia; peripheral nerve injury; spinal mu-opioid receptor; naloxone; CTOP
- Citation
- PAIN, v.123, no.1-2, pp 117 - 126
- Pages
- 10
- Indexed
- SCIE
SCOPUS
- Journal Title
- PAIN
- Volume
- 123
- Number
- 1-2
- Start Page
- 117
- End Page
- 126
- URI
- https://scholarworks.korea.ac.kr/kumedicine/handle/2020.sw.kumedicine/36073
- DOI
- 10.1016/j.pain.2006.02.017
- ISSN
- 0304-3959
1872-6623
- Abstract
- The present study investigated whether the loss of spinal mu-opioid receptors following peripheral nerve injury is related to mechanical allodynia. We compared the quantity of spinal mu-opioid receptor and the effect of its antagonists, such as naloxone and CTOP, on pain behaviors in two groups of rats that showed extremely different severity of mechanical allodynia 2 weeks following partial injury of tail-innervating nerves. One group (allodynic group) exhibited robust signs of mechanical allodynia after the nerve injury, whereas the other group (non-allodynic group) showed little allodynia despite having suffered the same nerve injury. In addition, we investigated the quantity of spinal p-opioid receptor and the effect of its antagonists on pain behaviors after the rats had recovered from mechanical allodynia, 16 weeks following nerve injury. Immunohistochemical and Western blot analyses at 2 weeks after nerve injury indicated that spinal mu-opioid receptor content was more reduced in the allodynic group compared to the non-allodynic group. Intraperitoneal naloxone (2 mg/kg, i.p.) and intrathecal CTOP (10 mu g/rat, i.t.) administration dramatically induced mechanical allodynia, in the non-allodynic group. However, as in naive animals, neither the loss of spinal mu-opioid receptors nor antagonist-induced mechanical allodynia was observed in the rats that had recovered from mechanical allodynia. These results suggest that the loss of spinal mu-opioid receptors following peripheral nerve injury is related to mechanical allodynia. (c) 2006 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.
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Collections - 1. Basic Science > Department of Physiology > 1. Journal Articles
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