The role of nitric oxide in spinal cord sensitization in a rat model of neuropathic pain
- VernacularTitle:一氧化氮在神经病理性痛大鼠脊髓敏化中的作用
- Author:
Changqi LIU
;
Jian WANG
;
Yongfeng MA
- Publication Type:Journal Article
- Keywords:
Nitric oxide;
Neuralgia;
Spinal;
Hyperalgesia
- From:
Chinese Journal of Anesthesiology
2008;28(3):256-258
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the role of nitric oxide(NO)in the spinal cord sensitization in a rat model of neuropathic pain.Methods Thirty-two male adult Wistar rats weighing 200-300 g were randomly divided into 4 groups with 8 animals in each group:group Ⅰ sham operation;group Ⅱ L-NAME pretreatment + sham operation;group Ⅲ CCI and group Ⅳ L-NAME pretreatment + CCI.Neuropathic pain was induced by chronic constrictive injury(CCI).The animals were anesthetized with intraperitoneal pentobarbital 40 mg/kg.The right sciatic nerve was exposed and 4 loose ligatures were placed on the sciatic nerve at 1 mm intervals with 3-0 silk thread.In group Ⅰ and Ⅱ the sciatic nerve was exposed but not ligated.In group Ⅲ and Ⅳ L-NAME 250 μg in normal saline 10 μl was injected into subarachnoid space over 30 seconds at 15 min before sham operation or CCI.The paw-withdrawal threshold to nociceptive thermal stimuli(PWTT)was measured before operation(baseline)and on the 3rd day after operation.Four rats in each group were killed on the 4th and 7th day after operation,and lumbar segment of the spinal cord(L4-5)was removed for determination of expression of pCREB in the dorsal horn of spinal cord by immuno-histochemical technique.Results The paw-withdrawal threshold to nociceptive thermal stimuli(PWTT)was significantly decreased on the 3rd day after operation as compared with the baseline before operation in all 4 groups.The PWTT on the 3rd day after operation was significantly higher in group Ⅰ,Ⅱ and Ⅳ than in CCI group(group Ⅲ),but there was no significant difference in the PWTT after operation among the 3 groups(Ⅰ,Ⅱ,Ⅳ).The expression of pCREB in the dorsal horn neurons of spinal cord was significantly upregulated in CCI group (Ⅲ) as compared with the other 3 groups.Conclusion Spinal cord NO induces hyperalgesia in neuropathic pain through release of pCREB in spinal cord dorsal horn.
