Spinal cord injury triggers sensitization of wide dynamic range dorsal horn neurons in segments rostral to the injury.
A spinal cord injury (SCI) was produced in adult rats by complete spinal cord transection at L6-S1. Neuropathic pain behaviors similar to the chronic central pain (CCP) syndrome in human, such as thermal hyperalgesia, mechanical allodynia and autotomy, were present in these rats after spinal cord injury. Meanwhile, wide dynamic range (WDR) neurons recorded in the spinal dorsal horn rostral to the lesion responded as high frequency of spontaneous activities, long duration of after-discharges to noxious electrical stimuli and an augmented wind-up to 0.5 Hz stimuli. By using bupivacaine powder, a sodium channel blocker, at the locus of transection immediate after nerve injury, the chronic pain behaviors were prevented; the hyperexcitability of WDR neurons was also substantially reduced. It is suggested that spinal cord transection induces the CCP syndromes, which may be evoked and maintained by the hyperexcitability in WDR neurons rostrally. Reducing the neuronal activity at the site of lesion following injury may prevent the development of CCP after SCI.
Zhang
Haijun
H
Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China.
Xie
Wenrui
W
Xie
Yikuan
Y
D000818:Animals; D001522:Behavior, Animal; D004558:Electric Stimulation / Q000009:adverse effects; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects; D006930:Hyperalgesia / Q000209:etiology / Q000503:physiopathology*; D010147:Pain Measurement; D010812:Physical Stimulation; D020671:Posterior Horn Cells / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D013119:Spinal Cord Injuries / Q000473:pathology* / Q000503:physiopathology