Neuroscience 2004 Abstract
| Presentation Number: | 941.9 |
|---|---|
| Abstract Title: | Activity and neurotrophins converge intracellularly to regulate axon competition in sympathetic neurons. |
| Authors: |
Singh, K. K.*1
; Miller, F. D.1
1Developmental Biol., The Hosp. for Sick Children, Toronto, Canada |
| Primary Theme and Topics |
Development - Axonal and Dendritic Development -- Axon growth and guidance: extracellular signals |
| Session: |
941. Axon Guidance V Poster |
| Presentation Time: | Wednesday, October 27, 2004 1:00 PM-2:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # C9 |
| Keywords: | AXON, GROWTH FACTOR, ACTIVITY |
One strategy used by the developing nervous system to ensure the establishment of appropriate connectivity is to overproduce axon collaterals and then to select only those that make correct connections. This is thought to be largely driven by activity and trophic factor-dependent axon competition. Here, we have asked how activity and one class of trophic factors, the neurotrophins, regulate this process of axon collateral selection using cultured sympathetic neurons in compartmented cultures as a model system. We show that in the presence of NGF, local depolarization confers a growth advantage on depolarized axon collaterals, acting both to enhance the rate of growth and to increase axonal density. This growth advantage occurs at the expense of unstimulated collaterals deriving from the same neurons which exhibit reduced axonal growth even when compared to axons from control neurons growing into the same amount of NGF. Depolarization mediates the enhanced growth of the stimulated axons by locally activating a CaMKII-MEK pathway, which converges to enhance local NGF-mediated downstream growth signals. Electrical field stimulation of sympathetic neurons also enhances NGF-promoted axonal branching and total axon growth via the same pathway. Thus, activity and growth factors collaborate locally via CaMKII-MEK signaling to confer a growth advantage on one axon collateral versus another, a mechanism that may well play an essential role both developmentally and during neural plasticity in the mature nervous system.
Supported by Supported by grants from the Canadian Institute for Health Research (CIHR)
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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