C- fos expression in the spinal cord of rats exhibiting allodynia following contusive spinal cord injury

• Published in: Brain research 1999-12, Vol.851 (1), p.281-286
• Main Authors: Siddall, Philip J., Xu, Cao Ling, Floyd, Nicole, Keay, Kevin A.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Genes, fos - physiology; Hypersensitivity; Immediate-early gene; Immunohistochemistry; Medical sciences; Nervous system (semeiology, syndromes); Nervous system as a whole; Neurology; Neuropathic pain; Posterior Horn Cells - metabolism; Rats; Spinal Cord Injuries - metabolism; Thoracic Vertebrae - injuries
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/S0006-8993(99)02173-3

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 allodynic 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.