Role of peripheral group I and II metabotropic glutamate receptors in IL-1beta-induced mechanical allodynia in the orofacial area of conscious rats.

Abstract

The present study investigated the role of peripheral group I and II metabotropic glutamate receptors (mGluRs) in interleukin-1beta (IL-1beta)-induced mechanical allodynia in the orofacial area. Experiments were carried out on Sprague-Dawley rats weighing between 230 and 280 g. After subcutaneous administration of 0.01, 0.1, 1, or 10 pg of IL-1beta, we examined withdrawal behavioral responses produced by 10 successive trials of a ramp of air-puffs pressure applied ipsilaterally or contralaterally to the IL-1beta injection site. The thresholds of air puffs were measured 10, 30, 60, 120, or 180 min after 25 microl of IL-1beta was administered through an implanted tube. Subcutaneous injection of IL-1beta produced bilateral mechanical allodynia. While the IL-1beta-induced mechanical allodynia was blocked by pretreatment with an IL-1 receptor antagonist, the IL-1beta-induced mirror-image mechanical allodynia was not blocked by an IL-1 receptor antagonist injected into the contralateral side. Subcutaneous administration of CPCCOEt or LY367385, an mGluR1 antagonist, or MPEP or SIB1893, an mGluR5 antagonist, 10 min prior to injection of IL-1beta abolished IL-1beta-induced mechanical allodynia. Pretreatment with APDC or DCG4, a group II mGluR agonist, blocked the IL-1beta-induced mechanical allodynia. The anti-allodynic effect induced by APDC was inhibited by pretreatment with LY341495, a group II mGluR antagonist. These results suggest that peripheral group I and II mGluRs participate in IL-1beta-induced mechanical allodynia in the orofacial area. Peripheral group I mGluR antagonists blocked the IL-1beta-induced mechanical allodynia, while peripheral group II mGluR agonists produced anti-allodynic effects on IL-1beta-induced mechanical allodynia in the orofacial area of rats.

• Authors: Dong K Ahn, Kwang H Kim, Chang Y Jung, Hyo S Choi, Eun J Lim, Dong H Youn, Yong C Bae
• Journal: Pain (Pain) Vol. 118 Issue 1-2 Pg. 53-60 (Nov 2005) ISSN: 0304-3959 [Print] United States
• PMID: 16154694 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 7-(hydroxyimino)cyclopropan(b)chromen-1a-carbxoylic acid ethyl ester
• Benzoates
• Chromones
• Excitatory Amino Acid Antagonists
• Interleukin-1
• Pyridines
• Receptors, Metabotropic Glutamate
• SIB 1893
• alpha-methyl-4-carboxyphenylglycine
• Glycine

Topics

• Air
• Animals
• Benzoates (pharmacology)
• Chromones (pharmacology)
• Consciousness (physiology)
• Excitatory Amino Acid Antagonists (pharmacology)
• Facial Pain (chemically induced, physiopathology, prevention & control)
• Functional Laterality
• Glycine (analogs & derivatives, pharmacology)
• Injections, Subcutaneous
• Interleukin-1
• Male
• Nociceptors (physiology)
• Pain Measurement
• Pain Threshold (physiology)
• Physical Stimulation (methods)
• Pyridines (pharmacology)
• Rats
• Rats, Sprague-Dawley
• Receptors, Metabotropic Glutamate (antagonists & inhibitors, physiology)