Neuroscience 2001 Abstract
| Presentation Number: | 698.17 |
|---|---|
| Abstract Title: | Inosine-enhanced sprouting of intact corticospinal tract (CST) axons into the denervated CST leads to enhanced synapse formation in the adjacent denervated neuropil. |
| Authors: |
Shah, P. J.*1
; Goldberg, D. E.2
; Aoki, C.1
; Benowitz, L. I.2
1Ctr for Neural Sci, NYU, New York, NY 2Children's Hosp Harvard Med Sch, Boston, MA |
| Primary Theme and Topics |
Development - Transplantation and Regeneration -- Regeneration |
| Secondary Theme and Topics | Development<br />- Synaptogenesis and Activity-Dependent Development<br />-- Synapse formation: CNS |
| Session: |
698. Transplantation and regeneration: regeneration VII Poster |
| Presentation Time: | Wednesday, November 14, 2001 8:00 AM-9:00 AM |
| Location: | Exhibit Hall B-70 |
| Keywords: | SYNAPTOGENESIS, REGENERATION, ELECTRON MICROSCOPY, GROWTH FACTOR |
Following unilateral CST transections, intracortical infusion of a purine nucleoside, inosine, induces a 10-fold increase in the number of intact CST axons in the spinal cord that cross the midline to enter the denervated dorsal funiculus(dDF) (Benowitz et al., PNAS 96: 13486-90). These collaterals form synapses that are identifiable by EM in the denervated synaptic neuropil, lamina IV (dIV), adjacent to dDF (Soni et al., SfN Abs 26,325.9). Here, we investigated whether the inosine-effect is also exhibited as the crossed, intact axons continue to grow through dDF and into dIV (axogenesis), then undergo synaptogenesis. Unilateral CST transection was performed as before in mature rats. One group (n=3) was treated with 50mM of inosine in PBS, delivered into the intact cortex (4 wks @ 0.25 ul/hr), while the second group (n=3) was infused with PBS, alone. BDA was injected into the intact cortex to identify their trajectory in the spinal cord. We observed that inosine increases the number of intact CST axons that (a) sprout through dDF,(b) into dIV and (c) form synapses there. On the other hand the portion of BDA axons in dIV, relative to those in dDF (b/a), as well as the portion of BDA axons in dIV forming synapses (c/b) is similar for both groups. We conclude that administration of inosine to intact pyramidal cells stimulates axon sprouting within denervated white matter. Once in dCST, these axons exhibit propensity to grow into the synaptic neuropil and form synapses there, independent of inosine.
Supported by Boston Life Sci Inc., C Reeve Paralysis Fdn, R01 EY05690, 1R01NS41091, 1P30EY13079
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2001 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2001. Online.
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