Microglial activation of p38 contributes to scorpion envenomation-induced hyperalgesia.

Abstract

Intraplantar (i.pl.) injection of BmK I, a receptor site 3-specific modulator of voltage-gated sodium channels (VGSCs) from the venom of scorpion Buthus martensi Karsch (BmK), was shown to induce long-lasting and spontaneous nociceptive responses as demonstrated through experiments utilizing primary thermal and mirror-imaged mechanical hypersensitivity with different time course of development in rats. In this study, microglia was activated on both sides of L4-L5 spinal cord by i.pl. injection of BmK I. Meanwhile, the activation of p38/MAPK in L4-L5 spinal cord was found to be co-expressed with OX-42, the cell marker of microglia. The unilateral thermal and bilateral mechanical pain hypersensitivity of rat induced by BmK I was suppressed in a dose-dependent manner following pretreatment with SB203580 (a specific inhibitor of p-p38). Interestingly, microglia activity was also reduced in the presence of SB203580, which suggests that BmK I-induced microglial activation is mediated by p38/MAPK pathway. Combined with previously published literature, the results of this study demonstrate that p38-dependent microglial activation plays a role in scorpion envenomation-induced pain-related behaviors.

• Authors: Qing-Shan Niu, Feng Jiang, Li-Ming Hua, Jin Fu, Yun-Lu Jiao, Yong-Hua Ji, Gang Ding
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 440 Issue 3 Pg. 374-80 (Oct 25 2013) ISSN: 1090-2104 [Electronic] United States
• PMID: 24064352 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2013 Elsevier Inc. All rights reserved.

Chemical References

• Imidazoles
• Pyridines
• Scorpion Venoms
• makatoxin I
• p38 Mitogen-Activated Protein Kinases
• SB 203580

Topics

• Animals
• Behavior, Animal
• Hyperalgesia (chemically induced, enzymology, psychology)
• Imidazoles (pharmacology)
• Lumbosacral Region
• Male
• Microglia (enzymology)
• Pyridines (pharmacology)
• Rats
• Rats, Sprague-Dawley
• Scorpion Venoms (pharmacology)
• Spinal Cord (drug effects, enzymology, physiopathology)
• p38 Mitogen-Activated Protein Kinases (antagonists & inhibitors, metabolism)