A role for G protein-coupled receptor kinase 2 in mechanical allodynia
Inflammation and nerve injury can both induce mechanical allodynia via mechanisms involving the production of pro‐inflammatory cytokines and increased neuronal activity. Many neurotransmitters involved in pain signal via G protein‐coupled receptors (GPCRs). GPCR kinase (GRK)2 is a member of the GRK...
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Published in | The European journal of neuroscience Vol. 25; no. 6; pp. 1696 - 1704 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford, UK
Blackwell Publishing Ltd
01.03.2007
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Subjects | |
Online Access | Get full text |
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Summary: | Inflammation and nerve injury can both induce mechanical allodynia via mechanisms involving the production of pro‐inflammatory cytokines and increased neuronal activity. Many neurotransmitters involved in pain signal via G protein‐coupled receptors (GPCRs). GPCR kinase (GRK)2 is a member of the GRK family that regulates agonist‐induced desensitization and signalling of GPCRs. Low intracellular GRK2 levels are associated with increased receptor signalling. The aim of this study was to investigate whether mechanical allodynia is associated with decreased spinal cord GRK2 expression and whether reduced GRK2 increases inflammation‐induced mechanical allodynia. Mechanical allodynia was induced in rats by chronic constriction injury of the sciatic nerve. After 2 weeks, neuronal GRK2 expression was decreased bilaterally in the superficial layers of the lumbar spinal cord dorsal horn. Moreover, interleukin‐1β significantly reduced GRK2 expression ex vivo in spinal cord slices. To investigate whether reduced GRK2 potentiates inflammation‐induced mechanical allodynia, we used GRK2+/– animals expressing decreased GRK2. At baseline, the threshold for mechanical stimulation did not differ between GRK2+/– and wild‐type mice. However, GRK2+/– animals were more sensitive to mechanical stimulation than wild‐type animals after intraplantar λ‐carrageenan injection. We propose cytokine‐induced down‐regulation of spinal cord neuronal GRK2 expression as a novel mechanism that contributes to increased neuronal signalling in mechanical allodynia. |
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Bibliography: | ark:/67375/WNG-5SXQ2C7X-J ArticleID:EJN5423 istex:686EBF84FEDA431BF586E3A908756B05B59F8190 Aigen, Inc., Alameda, CA, USA. Present address ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0953-816X 1460-9568 |
DOI: | 10.1111/j.1460-9568.2007.05423.x |