Antiallodynic effect through spinal endothelin-B receptor antagonism in rat models of complex regional pain syndrome.

Abstract

Complex regional pain syndrome (CRPS) is a very complicated chronic pain disorder that has been classified into two types (I and II). Endothelin (ET) receptors are involved in pain conditions at the spinal level. We investigated the role of spinal ET receptors in CRPS. Chronic post-ischemia pain (CPIP) was induced in male Sprague-Dawley rats as a model for CRPS-I by placing a tourniquet (O-ring) at the ankle joint for 3h, and removing it to allow reperfusion. Ligation of L5 and L6 spinal nerves to induce neuropathic pain was performed as a model for CRPS-II. After O-ring application and spinal nerve ligation, the paw withdrawal threshold was significantly decreased at injured sites. Intrathecal administration of the selective ET-B receptor antagonist BQ 788 dose-dependently increased the withdrawal threshold in both CRPS-I and CRPS-II. In contrast, ET-A receptor antagonist BQ 123 did not affect the withdrawal threshold in either CRPS type. The ET-1 levels of plasma and spinal cord increased in both CRPS types. Intrathecal BQ 788 decreased the spinal ET-1 level. These results suggest that ET-1 is involved in the development of mechanical allodynia in CRPS. Furthermore, the ET-B receptor appears to be involved in spinal cord-related CRPS.

• Authors: Yeo Ok Kim, In Ji Kim, Myung Ha Yoon
• Journal: Neuroscience letters (Neurosci Lett) Vol. 584 Pg. 45-9 (Jan 01 2015) ISSN: 1872-7972 [Electronic] Ireland
• PMID: 25451723 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Chemical References

• Endothelin B Receptor Antagonists
• Endothelin-1
• Oligopeptides
• Peptides, Cyclic
• Piperidines
• BQ 788
• cyclo(Trp-Asp-Pro-Val-Leu)

Topics

• Animals
• Causalgia (drug therapy, metabolism, physiopathology)
• Endothelin B Receptor Antagonists (pharmacology, therapeutic use)
• Endothelin-1 (metabolism)
• Hyperalgesia (drug therapy, metabolism, physiopathology)
• Male
• Oligopeptides (therapeutic use)
• Pain Threshold (drug effects)
• Peptides, Cyclic (therapeutic use)
• Physical Stimulation
• Piperidines (therapeutic use)
• Rats, Sprague-Dawley
• Reflex (drug effects)
• Reflex Sympathetic Dystrophy (drug therapy, metabolism, physiopathology)
• Spinal Cord (metabolism)
• Touch