首页 | 本学科首页   官方微博 | 高级检索  
     


Primary cultures as a model for studying ependymal functions: glycogen metabolism in ependymal cells
Authors:Christian Prothmann   John Wellard    rgen Berger   Bernd Hamprecht  Stephan Verleysdonk
Affiliation:

a Physiologisch-chemisches Institut der Universität, Hoppe-Seyler-Str. 4, D-72076 Tübingen, Germany

b Max-Planck-Institut für Entwicklungsbiologie, Spemannstr. 35, D-72076 Tübingen, Germany

Abstract:
Ependymal cells form a single-layered, ciliated epithelium at the interface between the cerebrospinal fluid and the brain parenchyma. Although their morphology has been studied in detail, ependymal functions remain largely speculative. We have established and characterized a previously described cell culture model to investigate ependymal glycogen metabolism. During growth in minimal medium lacking many non-essential amino acids including -glutamate, but containing glucose at physiological concentration, the cells contained negligible amounts of glycogen (7±3 nmol glucosyl residues/mg protein) despite the presence of insulin. However, during a period of 24 h, the cells accumulated glycogen to very high levels after transferal to a medium containing insulin, glucose at a 5-fold higher concentration, and all proteinogenic amino acids except -asparagine and -serine (990±112 nmol glucosyl residues/mg protein). Omission of insulin resulted in a 50% reduction in glycogen accumulation. Upon glucose deprivation, glycogen was degraded with a half-life of 21 min. The ependymal primary cultures contained 80±5 mU glycogen phosphorylase (Pho)/mg protein and stained positively with antibodies raised against this enzyme. Astroglial cultures built up less glycogen and had less Pho activity under identical conditions. Ependymal glycogen was mobilized by noradrenaline and serotonin. Our results indicate that ependymal cells maintain glycogen as a functional energy store, subject to rapid turnover dependent on the availability of energy substrates and the presence of appropriate signal molecules. Thus ependymocytes appear to be active players in the multitude of processes resulting in normal brain function, and ependymal primary cultures are suggested as a suitable model for studying the role of ependymal cells in these processes.
Keywords:Ependymal cell   Cell culture   Glial metabolism   Glycogen   Glycogen phosphorylase   Insulin
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号