Wu Jing, Fang Li, Lin Qing, Willis William D
Department of Anatomy and Neurosciences, Marine Biomedical Institute, University of Texas Medical Branch, Galveston, 77555, USA.
J Pain. 2002 Jun;3(3):190-8. doi: 10.1054/jpai.2002.123653.
We investigated the involvement of nitric oxide (NO) in the phosphorylation of cyclic adenosine monophosphate-responsive element-binding protein (CREB) in the spinal cord of rats during central sensitization after intradermal capsaicin injection. CREB and phosphorylated CREB (p-CREB) were measured by immunoblotting. The level of p-CREB increased by 20 minutes, peaked between 20 and 60 minutes after capsaicin injection, and started to decrease after 150 minutes. CREB itself did not show an obvious change after capsaicin injection. The p-CREB expression on the ipsilateral side of the spinal dorsal horn, but not on the contralateral side, increased significantly after capsaicin injection. The increase in p-CREB induced by capsaicin injection was partially blocked by pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor, administered through a microdialysis fiber placed across the spinal cord. D-NAME, an inactive form of L-NAME, had no effect. CREB phosphorylation, not the level of CREB, was induced within 20 minutes by microdialysis administration of SIN-1, an NO donor. These results indicate that CREB phosphorylation in the spinal cord results from both endogenous and exogenous NO release and that p-CREB may play a role in central sensitization or in longer-term changes in gene expression induced by strong peripheral noxious stimulation.
我们研究了在皮内注射辣椒素后大鼠脊髓中枢敏化过程中一氧化氮（NO）对环磷酸腺苷反应元件结合蛋白（CREB）磷酸化的影响。通过免疫印迹法检测CREB和磷酸化CREB（p-CREB）。p-CREB水平在20分钟时升高，在辣椒素注射后20至60分钟达到峰值，并在150分钟后开始下降。辣椒素注射后CREB本身未显示明显变化。辣椒素注射后，脊髓背角同侧而非对侧的p-CREB表达显著增加。通过置于脊髓上的微透析纤维给予NO合酶抑制剂N(G)-硝基-L-精氨酸甲酯（L-NAME）预处理，可部分阻断辣椒素注射诱导的p-CREB增加。L-NAME的无活性形式D-NAME则无作用。通过微透析给予NO供体SIN-1可在20分钟内诱导CREB磷酸化，但不影响CREB水平。这些结果表明，脊髓中CREB磷酸化是由内源性和外源性NO释放引起的，并且p-CREB可能在中枢敏化或由强烈外周有害刺激诱导的基因表达的长期变化中起作用。
