Fig. 5.

Local up-regulation of BDNF variants results in local phosphorylation of TrkB. (A) Immunofluorescence for full-length TrkB (green) and phosphorylated TrkB (red) in two similar hippocampal neurons treated for 3 h with 50 ng/mL BDNF. (B) Straightened dendrites of neurons labeled with an anti-TrkB (green) or transfected with the indicated GFP constructs and labeled with anti-pTrkB (red). Treatment with the TrkB inhibitor K252a abolishes staining for pTrkB, whereas addition of 50 ng/mL BDNF led to labeling for pTrkB throughout the entire dendrite length. (C) Semiquantitative densitometric analysis of pTrkB fluorescence intensity in neurons transfected with the different constructs. (**P < 0.01; ANOVA.)