Neuroscience 2005 Abstract
| Presentation Number: | 29.13 |
|---|---|
| Abstract Title: | Ultrastructural features of axon regeneration and reinnervation at the neuromuscular junction. |
| Authors: |
Lakia, B. M.*1
; Lira, M. E.1
; Walker, J.1
; Bishop, D. L.1
1Dept Med Educ, Indiana Univ., Muncie, IN |
| Primary Theme and Topics |
Development - Transplantation and Regeneration -- Regeneration: PNS |
| Session: |
29. Regeneration: PNS II Poster |
| Presentation Time: | Saturday, November 12, 2005 1:00 PM-2:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # C6 |
| Keywords: | DENERVATION, ELECTRON MICROSCOPY, SCHWANN CELL, SYNAPTOGENESIS |
Denervation is associated with neurodegenerative diseases and acute injuries in skeletal muscle. To promote functional recovery from denervation type injuries or disease processes, it is necessary for injured axons to regenerate and navigate back to their target to reestablish synapses. To better understand these processes at the neuromuscular junction, we crushed peripheral nerves in transgenic mice with cytoplasmic expression of yellow fluorescent protein (YFP) in their motoneurons and allowed them to regenerate to their former synaptic sites. We then used correlated confocal and serial electron microscopy to examine ultrastructural features of the regenerating axons prior to endplate arrival and during initial reoccupation of the denervated endplate. Using this approach, we found that the tips of regenerating axons contain no active zones and are guided to former endplates within tubes filled with hypertrophied Schwann cell processes. These axons do not appear to associate with basal lamina material. The distal tips of the regenerating axons contain a large endosomal network and appear to contain no active zones. Once the regenerating axon nears the endplate region, it associates with both synaptic basal lamina and small processes from terminal Schwann cells. Axon segments that associate with synaptic basal lamina sometimes contain active zones and a large component of synaptic organelles. Those that remain constrained by Schwann cell appear to contain no such synaptic specializations and are often guided away from the former synapse. Together, these results suggest that during skeletal muscle reinnervation, Schwann cells serve as a substrate for axon regeneration while synapse formation is induced by protracted contact with the basal lamina.
Supported by Muscular Dystrophy Assoc. and N.I.H (DLB)
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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