Warringa R A, van Berlo M F, Klein W, Lopes-Cardozo M
Laboratory of Veterinary Biochemistry, State University of Utrecht, The Netherlands.
J Neurochem. 1988 May;50(5):1461-8. doi: 10.1111/j.1471-4159.1988.tb03031.x.
Glial cells were isolated from 1-week-old rat brain and cultured in a serum-free medium supplemented with the hormones insulin, hydrocortisone, and triiodothyronine. After 1 week in culture the cell population consisted mainly of galactocerebroside-positive cells (GC+; oligodendrocytes), the remainder of the cells being positive for glial fibrillary acidic protein (GFAP+; astrocytes). Oligodendrocytes were selectively removed from the cultures by complement-mediated cytolysis. The activities of glutamine synthetase and of various marker enzymes were measured in the nonlysed cells remaining after complement treatment of the cultures and in the culture medium containing proteins of the lysed cells. We found that the cellular activity of glutamine synthetase decreased in parallel with the lysis of GC+ cells and that the activity of glutamine synthetase in the supernatant increased. The activity of glycerol-3-phosphate dehydrogenase, a marker enzyme for oligodendrocytes, was no longer detectable in complement-treated cultures and the activity of glutamine synthetase was markedly lowered, whereas the activity of lactate dehydrogenase was as high as in untreated cultures. The location of glutamine synthetase both in oligodendrocytes and in astrocytes was confirmed by double-label immunocytochemistry with antisera against glutamine synthetase, GC, and GFAP. We conclude that in this culture system glutamine synthetase is expressed in both types of glial cells and that the activity of lactate dehydrogenase is at least one order of magnitude higher in astrocytes than in oligodendrocytes.
从1周龄大鼠脑中分离出神经胶质细胞，并在补充了胰岛素、氢化可的松和三碘甲状腺原氨酸的无血清培养基中培养。培养1周后，细胞群体主要由半乳糖脑苷脂阳性细胞（GC+；少突胶质细胞）组成，其余细胞为胶质纤维酸性蛋白阳性（GFAP+；星形胶质细胞）。通过补体介导的细胞溶解从培养物中选择性去除少突胶质细胞。在对培养物进行补体处理后剩余的未裂解细胞以及含有裂解细胞蛋白质的培养基中，测量谷氨酰胺合成酶和各种标记酶的活性。我们发现，谷氨酰胺合成酶的细胞活性随着GC+细胞的裂解而平行下降，并且上清液中谷氨酰胺合成酶的活性增加。在补体处理的培养物中不再能检测到少突胶质细胞的标记酶甘油-3-磷酸脱氢酶的活性，谷氨酰胺合成酶的活性明显降低，而乳酸脱氢酶的活性与未处理的培养物中一样高。用抗谷氨酰胺合成酶、GC和GFAP的抗血清进行双重标记免疫细胞化学，证实了谷氨酰胺合成酶在少突胶质细胞和星形胶质细胞中的定位。我们得出结论，在这个培养系统中，谷氨酰胺合成酶在两种类型的神经胶质细胞中均有表达，并且星形胶质细胞中乳酸脱氢酶的活性比少突胶质细胞中至少高一个数量级。
