I. Introduction 1 II. Materials and methods 3 2.1 Primary cell culture and transfection 3 2.2 Viral vectors for TrkB knockdown 3 2.3 Immunocytochemistry 3 2.4 Preparation of QD-BDNF conjugate 4 2.5 Preparation of extracellular solution for live-cell imaging 4 2.6 Live cell imaging 4 2.7 Data analysis 4 III. Results 6 3.1 QD-mBDNF as a tool for monitoring endosomal mature BDNF in astrocytes 6 3.2 Optimal QD-mBDNF treatment condition for observing endosomal BDNF 6 3.3 Endosomal pathways processing QD-mBDNF in astrocytes 7 3.4 Transport of endocytosed QD-mBDNF is affected by increase in intracellular Ca2+ 8 IV. Discussion 9 V. Figure legends 11 VI. Figures 14 References 26 Abstract in Korea 28