Study on <Na^+> - <K^+> pump activity of glial cells in cortex from a warm-blooded animal.

温血动物皮层胶质细胞<Na^>-<K^>泵活性的研究。

• 批准号: 59570068
• 负责人: ONOZUKA Minoru
• 金额: $ 1.09万
• 依托单位: Gifu University (1986)Kanagawa Dental College (1984-1985)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1984
• 资助国家: 日本
• 起止时间: 1984 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-59570068/
• 关键词: Glial cell; <Na^+> - <K^+> pump; potassium; sodium; ATPase activity; cerebral cortex

The characteristics of a glial <Na^+> - <K^+> pump dependent on extracellular <K^+> within epileptogenic cortex were studied electrophysiologically, biochemically and histochemically in vitro using slices from either cobalt- or kainic acid-induced epileptogenic cortex of rat. When the extracellular <K^+> concentration ([ <K^+> ]) was varied between 4 and 40 mM, the mean slope of membrane potential plotted against <[K^+]+o> was about 57 mV in glia from the normal cortex (tissue A) and about 44 mV in glia from the epileptogenic cortex (tissue B); whereas no significant difference in the resting membrane potential of these tissues was observed. In glia from tissue B, a marked transient hyperpolarizarion above control level was caused by replacement of elevated <[K^+]_o> with the normal medium. Ouabain abolished these phenomena observed in glia from tissue B, but had no effect on the membrane potential during normal <[K^+]_o> . Reduction of extracellular <Na^+> , <Ca^(2+)> and <Cl^-> did not significantly affect the membrane potential of glia from either tissue, In tissue A, the cells marked by intracellular injection of horseradish peroxidase after intracellular recording were protoplasmic astrocytes; in tissue B, fibrous astrocyte with abnormal processes predominated. <K^+> -dependent stimulation of ( <Na^+> , <K^+> )-ATP-ase activity of the astrocyte-enriched fraction and its membrane preparation from tissue B was much larger than that from tissue A. A certain amount of the reaction product of <K^+> -pNPPase activity was seen on glial plasma membrane within tissue B but not on that from tissue A. These results suggest that epileptogenic cortex may be modified to increase in its activity.

利用钴酸和凯尼克酸诱导的大鼠癫痫皮质片，从电生理学、生物化学和组织化学的角度研究了大鼠癫痫皮质内依赖细胞外<K^+>的神经胶质<Na^+> - <K^+>泵的特性。当细胞外<K^+>浓度（[<K^+>]）在4 ~ 40 mM范围内变化时，正常皮层（组织A）的神经胶质细胞对<[K^+]+o>的膜电位平均斜率约为57 mV，致痫性皮层（组织B）的神经胶质细胞对<K^+>)的膜电位平均斜率约为44 mV；而这些组织的静息膜电位无显著差异。在来自B组织的胶质细胞中，升高的<[K^+]_o>被正常介质取代，导致了高于对照水平的明显的瞬态超极化。瓦巴因消除了B组织胶质细胞的这些现象，但对正常<[K^+]_o>时的膜电位无影响。细胞外<Na^+>, <Ca^(2+)>和<Cl^->的减少对两种组织的胶质细胞的膜电位均无显著影响。在组织A中，细胞内记录后细胞内注射辣根过氧化酶标记的细胞为原生质星形胶质细胞；B组织中以突状异常的纤维星形胶质细胞为主。<K^+>, <K^+>)- atp酶活性对B组织星形胶质细胞富集部分及其膜制备的依赖性刺激远大于A组织。在B组织内的胶质质膜上可见一定量的<K^+> -pNPPase活性的反应产物，而在A组织内则未见。这些结果提示，可能对致痫皮质进行修饰以增加其活性。

项目成果

Minoru Onozuka: Brain Research,in press.(1987)

小野稔：大脑研究，出版中。（1987）

Minoru Onozuka: "Stimulation of synapsin 1 phosphorylation in synaptosomes by convulsants." Experimental Neurology. 94. 802-807 (1986)

Minoru Onozuka：“惊厥刺激突触体中的突触蛋白 1 磷酸化。”

Shizuko Imai: "Use of N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide and N-(6-aminohexyl)-1-naphthalenesulfonamide to determine <Ca^(2+)> /calmodulin-dependent events linking <Ca^(2+)> influx in rat cortical synaptosomes." Experientia, in press.(1987)

Shizuko Imai：“使用 N-(6-氨基己基)-5-氯-1-萘磺酰胺和 N-(6-氨基己基)-1-萘磺酰胺来确定 <Ca^(2 )> /钙调蛋白依赖性事件关联 <Ca