FORSKOLIN EFFECTS ON GLIAL AND CEREBROMICROVASCULAR CULTURES

环核苷酸在生长控制和分化中的作用尚不清楚。 悬而未决 最近可用的毛喉素，一种药物， 刺激腺苷酸环化酶的催化亚基，允许研究 从一个新的角度探讨cAMP对脑细胞生长的调节作用。 胶质 脑微血管内皮细胞和平滑肌细胞， 用于该体外研究。 cAMP产生，胸苷掺入， 并观察形态学和细胞骨架变化。 结果表明，在所有三种细胞类型中， 掺入量呈剂量依赖性降低，具有最大生长抑制作用 100 μ M的毛喉素 一个小时的预孵育与毛喉素废除 含胎牛血清（FCS）的培养基中的胸苷掺入超过 接下来的24小时。 暴露于毛喉素也导致了剧烈的， 内皮细胞形态学和F-actin组成即时变化 和平滑肌 这些变化是可逆的。 在神经胶质细胞中 形态学变化仅在暴露于毛喉素后可见， 超过24小时 这些变化伴随着染色增加， 抗神经胶质细胞酸性蛋白的抗体。 这些发现支持cAMP在这些细胞的生长调节中的作用， 表明毛喉素可用作诱导生长停滞工具， 最终在哺乳动物脑的细胞培养物中分化。

The role of cyclic nucleotides in growth control and differentiation is yet unresolved. The recent availability of forskolin, a drug which directly stimulates the catalytic subunit of adenylate cyclase, allowed to study growth regulation of brain cells by cAMP from a new viewpoint. Glial cells, endothelium and smooth muscle cells from brain microvessels were used for this in-vitro study. cAMP production, thymidine incorporation, and morphological and cytoskeletal changes were examined. The results demonstrated that in all three cell types, thymidine incorporation was reduced dose-dependently with maximal growth inhibition at 100 MuM forskolin. A one hour preincubation with forskolin abolished thymidine incorporation in fetal calf serum (FCS)-containing medium over the following 24 hours. Exposure to forskolin led also to drastic and immediate changes of cell morphology and F-actin composition in endothelium and smooth muscle. These changes were reversible. In glial cells morphologic changes were visible only after exposure to forskolin for more than 24 hours. These changes were accompanied by increased staining with antibodies against glial fibrillary acidic protein. The findings support a role of cAMP in growth regulation of these cells and indicate that forskolin might be used as a tool to induce growth arrest and eventually differentiation in cell cultures from mammalian brain.