Alderson R F, Curtis R, Alterman A L, Lindsay R M, DiStefano P S
Regeneron Pharmaceuticals Inc., 777 Old Saw Mill River Road, Tarrytown, NY 10591-6707, USA.
Brain Res. 2000 Jul 21;871(2):210-22. doi: 10.1016/s0006-8993(00)02428-8.
Binding and cross-linking studies with radiolabeled neurotrophins demonstrate that cultured rat hippocampal astrocytes lack full-length TrkB, but do express high levels of truncated TrkB (tTrkB). In astrocytes and Schwann cells, tTrkB appears to have the novel function of mediating the endocytosis of neurotrophins into an acid-stable, Triton X-100 resistant intracellular pool that is released back into the medium in a temperature-dependent manner. Chloroquine treatment, trichloroacetic acid solubility, and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that when incubated with astrocytes or Schwann cells for at least 48 h neither the intracellular nor the released neurotrophins were significantly degraded. The endocytosis and release of neurotrophins may represent a novel mechanism whereby neuroglia can regulate the local concentration of these neurotrophic factors for extended periods of time.
用放射性标记的神经营养因子进行的结合和交联研究表明，培养的大鼠海马星形胶质细胞缺乏全长TrkB，但确实表达高水平的截短型TrkB（tTrkB）。在星形胶质细胞和雪旺细胞中，tTrkB似乎具有将神经营养因子内吞到酸稳定、抗Triton X-100的细胞内池的新功能，该池以温度依赖的方式释放回培养基中。氯喹处理、三氯乙酸溶解性和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析表明，当与星形胶质细胞或雪旺细胞孵育至少48小时时，细胞内和释放的神经营养因子均未显著降解。神经营养因子的内吞和释放可能代表一种新机制，通过该机制神经胶质细胞可以长时间调节这些神经营养因子的局部浓度。
