The study of protein associated with seizure-susceptibility in El mouse brain as a model of epilepsy

将从大脑、间脑、桥脑、延髓和小脑四个部位分离到的多聚体信使RNA与蛋氨酸共同孵育在兔网织红细胞裂解液中。孵育后，对翻译产物进行双向凝胶电泳法分析。共检测到20种蛋白质，其中小脑P蛋白在小脑中的表达高于其他部位，但少于ddy小鼠。全脑mRNA翻译产物比较显示，癫痫发作后即刻标记蛋白P显著降低，30min后恢复到正常水平。在突触质膜上，钙和钙调素联合作用可显著刺激皮层和海马区相对分子质量为200K和15OKd的蛋白的掺入，而对杏仁核中的200OKd、10OKd和20Kd蛋白以及海马区的20OKd蛋白的掺入有明显的抑制作用。El和ddy小鼠在海马和杏仁核中钙调素蛋白激酶II活性差异显著，皮质代词较少，隔核、纹状体、丘脑和小脑中钙调素蛋白激酶II活性差异不显著。因此，海马体和杏仁核可能是导致这种动物癫痫发作的原因。编码蛋白P或钙调素蛋白激酶II的信使核糖核酸的种类还需要进一步的实验研究，针对这类蛋白的特异的cDNA探针的分子克隆将为阐明癫痫的发病机制提供基础。

Polysomal messenger RNAs (mRNA) isolated from four parts of brain such as cerebrum, diencephalon, pons and medulla oblongata, and cerebellum were incubated with [^<35>S]-methionine in rabbit reticulocyte lysate system. After the incubation, translation products were analyzed by two dimensional gel electrophoresis. There were twenty proteins, in which protein P of El mice was more labeled in cerebellum than in other parts, but less than that of ddY mice. Comparison of translation products of mRNA from whole brain indicated that labeled protein P significantly decreased immediately after the seizures and after 30 min it restored to normal level. These results suggest that mRNA regulated protein P synthesis is associated with seizure-diathesis.In the synaptic plasma membranes of El mice, ^<32>P incorporation into proteins of molecular weights 200K in cortex and 15OKd in hippocampus was markedly stimulated by combined calcium and calmodulin, whereas it showed a significant inhibition of 20OKd, 10OKd, and 2OKd proteins in amygdala, and 2OKd in hippocampus. The difference of Ca^<2+>-calmodulin kinase II activity between El and ddY mice was remarkable in both hippocampus and amygdala, less pronouns in cortex, and not significant in septa, striatum, thalamus and cerebellum. Thus, hippocampus and amygdala may be responsible for induced-seizure of this animal. Further experiments are need to investigate mRNA species coding for protein P or Ca^<2+>-calmodulin kinase II, and the molecular cloning of cDNA probes being specific relative to such proteins will provide a basis to elucidate the epileptogenesis.