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. Author manuscript; available in PMC: 2011 Apr 1.
Published in final edited form as: Dev Neurobiol. 2010 Apr;70(5):304–322. doi: 10.1002/dneu.20765

Figure 3. BDNF bead application to a short dendritic segment facilitates PSD-95-GFP FRAP throughout the dendritic tree of locally-stimulated neurons.

Figure 3

(a) (Top row) BDNF covalently linked to a bead (pseudo-colored red) was placed in contact with one dendritic branch and a dendritic segment nearby (white square) was bleached. (Middle row) A segment of a completely separate dendrite was bleached after a BDNF-coated bead was applied. (Bottom row) A group of BDNF-coated beads was placed near a dendrite without contact. Scale, 10 µm.

(b) Magnified images of dendrites inside the white squares in Fig. 6(a). The branches from a neuron contacting the BDNF-coated bead or a separate dendritic branch from a neuron with a BNDF-coated bead contacting another one of its dendrites, show a more pronounced FRAP of PSD-95-GFP than a branch from the neuron with near-by beads that have no dendritic contact. Each image corresponds to a 21 µm × 21 µm bleached frame. Filled arrowheads in the second row identify weak puncta and their recovery in a dendrite that was expressing relatively low intensity PSD-95 puncta.

(c) FRAP graph summarizing the results of the dendrite-wide BDNF-bead-mediated PSD-95-GFP FRAP. Application of BDNF-coated beads to one dendrite of transfected neurons showed significantly facilitated PSD-95-GFP FRAP on distant dendrites of the same cells. Beads coated only with BSA and touching a dendrite had no effect above baseline on PSD-95-GFP FRAP in the dendrites of the contacted cell. Dendrites of nearby cells that were not contacted by beads covalently coated with BDNF showed the same baseline FRAP response seen with the BSA-coated beads. This lack of effect indicates that the PSD-95-GFP FRAP shown by dendrites distant from the one contacted by the BDNF bead were not driven by trace amounts of BDNF escaping from the bead. FRAP with bead treatments are shown against shaded areas reflecting the difference between baseline FRAP and FRAP with BDNF in the perfusion fluid. P=0.02 Error bar, s.e.m. (Adopted from Yoshii and Constantine-Paton, 2007)