C-fos expression in the spinal cord of rats exhibiting allodynia following contusive spinal cord injury.
Contusive spinal cord injury (SCI) may result in central neuropathic pain marked by allodynia-like features in the dermatomes close to the level of injury. The aim of this study was to compare the laminar distribution of activated neurons (as determined by c-fos immediate early gene expression) in the spinal cord immediately above the level of a SCI in rats with or without allodynia-like features. Non-noxious mechanical stimulation was applied to half the animals in the dermatomes corresponding to the level of injury prior to perfusion. Stimulation resulted in a significant increase in c-fos labelling in all laminae of the spinal dorsal horn in the segment immediately above the level of injury only in allodynia animals. Animals that had allodynia also demonstrated a significant increase in the level of c-fos labelling in lamina III, IV and V of the dorsal horn without stimulation. Thus, allodynia following SCI is associated with significant increases in basal and evoked c-fos expression ("neuronal activity") in response to non-noxious mechanical stimulation. The data also suggest that allodynia-like behaviour following SCI cannot be accounted for solely by changes occurring at a spinal level.
Siddall
P J
PJ
Pain Management and Research Centre, University of Sydney, Royal North Shore Hospital, St. Leonards, NSW, Australia. phils@med.usyd.edu.au
Xu
C L
CL
Floyd
N
N
Keay
K A
KA
D000818:Animals; D016762:Genes, fos / Q000502:physiology*; D020671:Posterior Horn Cells / Q000378:metabolism*; D051381:Rats; D013119:Spinal Cord Injuries / Q000378:metabolism*; D013904:Thoracic Vertebrae / Q000293:injuries