Abstract |
Patients suffering from sensory neuropathy due to skin denervation frequently have paradoxical manifestations of reduced nociception and neuropathic pain. However, there is a lack of satisfactory animal models to investigate these phenomena and underlying mechanisms. We developed a mouse system of neuropathy induced by resiniferatoxin (RTX), a capsaicin analog, and examined the functional significance of P2X3 receptor in neuropathic pain. From day 7 of RTX neuropathy, mice displayed mechanical allodynia (p<0.0001) and thermal hypoalgesia (p<0.0001). After RTX treatment, dorsal root ganglion (DRG) neurons of the peripherin type were depleted (p=0.012), while neurofilament (+) DRG neurons were not affected (p=0.62). In addition, RTX caused a shift in neuronal profiles of DRG: (1) increased in P2X3 receptor (p=0.0002) and ATF3 (p=0.0006) but (2) reduced TRPV1 (p=0.036) and CGRP (p=0.015). The number of P2X3(+)/ATF3(+) neurons was linearly correlated with mechanical thresholds (p=0.0017). The peripheral expression of P2X3 receptor in dermal nerves was accordingly increased (p=0.016), and an intraplantar injection of the P2X3 antagonists, A-317491 and TNP-ATP, relieved mechanical allodynia in a dose-dependent manner. In conclusion, RTX-induced sensory neuropathy with upregulation of P2X3 receptor for peripheral sensitization of mechanical allodynia, which provides a new therapeutic target for neuropathic pain after skin denervation.
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Authors | Yu-Lin Hsieh, Hao Chiang, June-Horng Lue, Sung-Tsang Hsieh |
Journal | Experimental neurology
(Exp Neurol)
Vol. 235
Issue 1
Pg. 316-25
(May 2012)
ISSN: 1090-2430 [Electronic] United States |
PMID | 22391132
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved. |
Chemical References |
- Diterpenes
- Receptors, Purinergic P2X3
- resiniferatoxin
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Topics |
- Animals
- Diterpenes
- Ganglia, Spinal
(metabolism, physiopathology)
- Hyperalgesia
(chemically induced, metabolism, physiopathology)
- Male
- Mice
- Mice, Inbred ICR
- Neuralgia
(chemically induced, metabolism, physiopathology)
- Neurons
(metabolism)
- Pain Measurement
- Peripheral Nervous System Diseases
(chemically induced, metabolism, physiopathology)
- Receptors, Purinergic P2X3
(metabolism)
- Skin
(innervation, metabolism, physiopathology)
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