Neuroscience 2000 Abstract
| Presentation Number: | 317.2 |
|---|---|
| Abstract Title: | BDNF modulates the dynamics of axon arborization and synapse formation <I>in vivo</I>. |
| Authors: |
Alsina, B.*1
; Vu, T.1
; Cohen-Cory, S.1
1MMRC, Depts. of Psychiatry and Neurobiology, UCLA, Los Angeles, CA |
| Primary Theme and Topics |
A. Development and Regeneration - 12. Biologic effects of trophic factors: neurotrophins |
| Secondary Theme and Topics | A. Development and Regeneration<br />- 8. Formation and specificity of synapses |
| Session: |
317. Biologic effects of trophic factors: neurotrophins II Poster |
| Presentation Time: | Monday, November 6, 2000 2:00 PM-3:00 PM |
| Location: | Hall G-J |
| Keywords: | Retinal Ganglion Cells, Xenopus, GFP-Synaptobrevin, Confocal Microscopy |
During development, neural cells migrate, extend their axons, arborize and establish appropriate connections with their target cells. Extensive axon arbor remodeling (branch extension and retraction) presumably occurs in conjunction with synapse formation and elimination. We have previously shown that BDNF plays a relevant role during axon arborization, but the question whether the acquired axon arbor complexity correlates with synapse formation remained unresolved. In order to examine the role of BNDF during synapse formation in vivo, we have fluorescently labeled individual Xenopus retinal axons to visualize their morphology while simultaneously expressed a fluorescent chimeric synaptic vesicle protein to selectively visualize sites of synaptic contact at a single cell level. A mixture of two plasmids encoding the Red Fuorescence Protein (RFP) and the fusion protein GFP-Synaptobrevin (Wang and Poo, Soc. Neurosc. Abstr., 1996; Cohen-Cory et al., Soc. Neurosc. Abstr., 1999) were lipofected into the eye of stage 22-24 embryos. Time-lapse confocal microscopy was used to follow double-labeled retinal ganglion cell axon arbors over time after tectal injection of BDNF (200ng/μl) or control solution in stage 45 tadpoles. Both individual optical sections and three-dimensional reconstructions of the arbors were analyzed to reveal synaptic vesicle distribution to particular areas (i.e. branches) within the individual arborizing retinal axons. Analysis of axon branch dynamics, number and distribution of synaptic vesicle clusters per branch, and of synaptic vesicle cluster dynamics, reveals that in comparison with controls, BDNF not only increases the complexity of axonal arbors over time but also increases the number of presumptive synaptic contacts. Thus, by specifically labeling individual synaptic proteins and simultaneously following synaptic vesicle and axon arbor dynamics over time, we provide first time evidence on the correlation between morphological changes in axon arbor complexity and formation of synaptic contacts at a single cell level, and of its modulation by BDNF.
Supported by Beckman Foundation and NEI EY11912 grant.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2000 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2000. Online.
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