Korean J Pain.  2010 Jun;23(2):109-115. 10.3344/kjp.2010.23.2.109.

Central Pain from Excitotoxic Spinal Cord Injury Induced by Intraspinal NMDA Injection: A Pilot Study

• Leem YJ
• Joh JW
• Joeng KW
• Suh JH
• Shin JW
• Leem JG

• KMID: 1770542
• DOI: http://doi.org/10.3344/kjp.2010.23.2.109

Abstract

BACKGROUND
The pathophysiological and neurochemical changes following spinal injury are not yet elucidated. This study was designed to evaluate the morphological changes of the dorsal horn of the spinal cord and profiles of pain behaviors following intraspinal injection of NMDA in rats.
METHODS
Rats were randomized into three groups: a sham-operated control group and groups where the rats received 10 mM or 100 mM N-methyl-D-aspatate (NMDA) injected into their spinal dorsal horn. Following injection, hypersensitivity to cold and mechanical stimuli and excessive grooming behaviors were assessed serially for four weeks. Morphological changes of the spinal cord were evaluated four weeks after intraspinal injection.
RESULTS
Few animals in the NMDA groups developed hypersensitivity to cold and mechanical stimuli. The number of groomers and the severity of excessive grooming were significantly higher in the 100 mM NMDA group than those values of the control and 10 mM NMDA groups. The size of the neck region (lamina III-IV) was significantly smaller in the 100 mM NMDA group than in the control and 10 mM NMDA groups.
CONCLUSIONS
In conclusion, intraspinal injection of NMDA in rats leads to the pathological sequela in the spinal cord and to excessive grooming behavior. These results support the use of NMDA and excessive grooming behavior after excitotoxic SCI as a model to study chronic pain after SCI.

Keyword

central pain; NMDA; rat; spinal cord injury

MeSH Terms

Animals
Chronic Pain
Cold Temperature
Grooming
Horns
Hypersensitivity
Injections, Spinal
N-Methylaspartate
Neck
Pilot Projects
Rats
Spinal Cord
Spinal Cord Injuries
Spinal Injuries
N-Methylaspartate