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磷酸化钙/钙调蛋白依赖性蛋白激酶Ⅱ在大鼠脊髓背角C-纤维诱发电位长时程增强的诱导和维持中的作用

信文君, 黎明涛, 杨红卫, 张红梅, 胡能伟, 胡晓东, 张彤, 刘先国

中山大学中山医学院生理学教研室.广东,广州 510089；中山大学中山医学院药理学教研室.广东,广州 510089

摘要

实验旨在探讨钙/钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)在脊髓背角C-纤维诱发电位长时程增强(LTP)的诱导和维持中的作用。用Western blot技术分别检测LTP形成30min和3h脊髓背角(L4-L6)CaMKⅡ的含量及其磷酸化水平。同时观察脊髓局部给予CaMKⅡ选择性抑制剂KN-93后对脊髓背角LTP和CaMKⅡ磷酸化的影响。观察结果如下:(1)诱导LTP后30min,CaMKⅡ的磷酸化水平明显高于对照组,而CaMKⅡ的总量无变化;诱导LTP后3h CaMKⅡ的磷酸化水平进一步升高,而且CaMKⅡ的总量也明显增加(n=4);(2)强直刺激前30min于脊髓局部给予CaMKⅡ的特异性抑制剂KN-93(100#mu#mol/L),可阻断LTP的诱导,同时明显抑制CaMKⅡ的磷酸化水平;(3)诱导LTP后30min给予KN-93,可显著抑制LTP的维持,同时CaMKⅡ的磷酸化水平与未用药组相比也明显降低(n=3);(4)LTP 3h后给予KN-93,LTP的幅值不受影响,磷酸化的CaMKⅡ的含量与用药前相比也无差别(n=3)。根据上述实验结果可以认为,CaMKⅡ的激活参与脊髓背角C-纤维诱发电位LTP的诱导和早期维持过程。

关键词： 钙/钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ); KN-93; 电位长时程增强(LTP); 脊髓背角; 蛋白质印迹(Westem blot)

Role of phospho-calcium/calmodulin-dependent protein kinase Ⅱ in the induction and maintenance of long-term potentiation of C-fiber-evoked field potentials in spinal dorsal horn of the rat

Xin Wenjun, Li Mingtao, Yang Hongwei, Zhang Hongmei, Hu Nengwei, Hu Xiaodong, Zhang Tong, Liu Xianguo

Department of Physiology,Zhongshan Medical School of Sun Yat-Sen University.Guangzhou 510089,Guangdong；China

Abstract

Our previous studies have shown that long-term potentiation (LTP) of C-fiber-evoked field potentials in the spinal dorsal horn is NMDA receptor dependent. it is known that elevation of Ca~(2+) in the postsynaptic neurons through NMDA receptor channels during high-frequency stimulation of the afferent fibers is crucial for LTP induction, but how this leads to a prolonged potentiation of synaptic transmission in the spinal dorsal horn is not clear. In the hippocampus, a rise of Ca~(2+) activates calcium/calmodulin-dependent protein kinase II (CaMK II) through autophosphorylation. Once this occurs, the kinase remains active, even when Ca~(2+) concentration returns to baseline level. Phosphorylated CaMK II potentiates synaptic transmission by enhancement of AMPA receptor channel function via phosphorylation of GluR1 subunit of the receptor and the addition of AMPA receptors to synapses.

Key words: calcium/calmodulin-dependent protein kinase II (CaMK II);KN-93;long-term potentiation (LTP);spinal dorsal cord;Western blot

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引用本文：

信文君, 黎明涛, 杨红卫, 张红梅, 胡能伟, 胡晓东, 张彤, 刘先国. 磷酸化钙/钙调蛋白依赖性蛋白激酶Ⅱ在大鼠脊髓背角C-纤维诱发电位长时程增强的诱导和维持中的作用[J]. 生理学报 2004; 56 (1): .

Xin Wenjun, Li Mingtao, Yang Hongwei, Zhang Hongmei, Hu Nengwei, Hu Xiaodong, Zhang Tong, Liu Xianguo. Role of phospho-calcium/calmodulin-dependent protein kinase Ⅱ in the induction and maintenance of long-term potentiation of C-fiber-evoked field potentials in spinal dorsal horn of the rat. Acta Physiol Sin 2004; 56 (1): (in Chinese with English abstract).