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Group III metabotropic glutamate receptors are involved in peripheral nociception
Author(s) -
Yang XiaoRong,
Zhang Yu,
Zhao Xin,
Qin LiRong,
Liu NaiHong,
Kang YuMing,
Qiao JianTian,
Zhang Ce
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a776-d
Subject(s) - nociception , peripheral , metabotropic glutamate receptor , nociceptor , metabotropic receptor , agonist , receptor , neuroscience , glutamate receptor , noxious stimulus , chemistry , spinal cord , medicine , pharmacology , biology
The present study is to investigate if group III mGluRs are involved in peripheral nociception by observing both nociceptive behavioral responses and Fos expression in spinal cord using the formalin model in rats. Behavioral observations showed that subcutaneous injection of group III mGluRs agonist L‐SOP (250 nmol, n=5) resulted in significant reduction in the second phase of the nociceptive responses. In c‐fos immunocytochemical examinations, results showed that peripheral pretreatment of L‐SOP (250 nmol, n=5) significantly decreased the Fos expression in spinal dorsal horn induced by peripheral formalin injection. Results stated above clearly suggested that group III mGluRs are involved in the processing of peripheral nociceptive signals, however, activation of these receptors suppressed rather than facilitated the generation of noxious inputs. It is the first time to report that group III mGLuRs are involved in the peripheral nociception. It has been well known that group III mGluRs are negatively coupled the AC, while the cAMP/PKA system activated by tissue damage or inflammation is critical in the initiation of noxious inputs. Taken together, one of the mechanisms that activation of group III mGluRs suppressed the peripheral nociception is inhibition of the cAMP/PKA mediated activation of peripheral nociceptors. Conclusions: Activation of peripheral group III mGluRs inhibits rather than facilitates the initiation of peripheral noxious inputs, the underlying mechanisms might be involved in cAMP/PKA mediated activation of peripheral nociceptors.