The contribution of autophosphorylated alpha-calcium-calmodulin kinase II to injury-induced persistent pain.
Increases in neuronal activity in response to tissue or nerve injury can lead to prolonged functional changes in the spinal cord resulting in an enhancement/sensitization of nociceptive processing. To assess the contribution of alpha-calcium-calmodulin kinase II (alpha-CaMKII) to injury-induced inflammation and pain, we evaluated nociceptive responses in mice that carry a point mutation in the alpha-CaMKII gene at position 286 (threonine to alanine). The mutated protein is unable to autophosphorylate and thus cannot function independently of calcium and calmodulin. Responses to acute noxious stimuli did not differ between alpha-CaMKII T286A mutant and wild type mice. However, the ongoing pain produced by formalin injury was significantly reduced in the mutant mice, as was formalin-evoked spinal Fos-immunoreactivity. In contrast, the decreased mechanical and thermal thresholds associated with nerve injury, Complete Freund's Adjuvant-induced inflammation or formalin-evoked tissue injury were manifest equally in wild-type and mutant mice. Double-labeling immunofluorescence studies revealed that in the mouse alpha-CaMKII is expressed in the superficial dorsal horn as well as in a population of small diameter primary afferent neurons. In summary, our results suggest that alpha-CaMKII, perhaps secondary to an N-methyl-D-aspartate-mediated calcium increase in postsynaptic dorsal horn nociresponsive neurons, is a critical contributor to the spontaneous/ongoing component of tissue-injury evoked persistent pain.
Departments of Anatomy and Physiology and the W. M. Keck Foundation Center for Integrative Neuroscience, University of California at San Francisco, San Francisco, CA 94080, USA. karla.zeitz@elan.com
K P
KP
Zeitz
K P
KP
Giese
A J
AJ
Silva
A I
AI
Basbaum
D000818:Animals; D001522:Behavior, Animal; D002118:Calcium / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002452:Cell Count / Q000379:methods; D004487:Edema / Q000473:pathology; D005620:Freund's Adjuvant; D005727:Ganglia, Spinal / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D007381:Intermediate Filament Proteins / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009619:Nociceptors / Q000502:physiology; D016761:Oncogene Proteins v-fos / Q000378:metabolism; D010146:Pain / Q000201:enzymology* / Q000209:etiology; D010147:Pain Measurement; D017288:Pain Threshold; D064531:Peripherins; D010766:Phosphorylation; D010812:Physical Stimulation / Q000379:methods; D011493:Protein Kinase C / Q000378:metabolism; D011930:Reaction Time / Q000235:genetics; D013373:Substance P / Q000378:metabolism; D013997:Time Factors; D012668:Trigeminal Ganglion / Q000378:metabolism; D014947:Wounds and Injuries / Q000150:complications*
D006023:Glycoproteins; D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D016761:Oncogene Proteins v-fos; D064531:Peripherins; C473590:isolectin B4-binding glycoprotein, mouse; D013373:Substance P; D005620:Freund's Adjuvant; C087857:protein kinase C gamma; D011493:Protein Kinase C; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C517671:Camk2a protein, mouse; D002118:Calcium