Development of connections by axons growing through injured spinal cord of neonatal opossum in culture

Détails

ID Serval
serval:BIB_34C60ACCE181
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Development of connections by axons growing through injured spinal cord of neonatal opossum in culture
Périodique
Journal of Experimental Biology
Auteur(s)
Woodward  S. K., Treherne  J. M., Knott  G. W., Fernandez  J., Varga  Z. M., Nicholls  J. G.
ISSN
0022-0949 (Print)
Statut éditorial
Publié
Date de publication
03/1993
Volume
176
Pages
77-88
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Mar
Résumé
The ability of neurites to grow through a lesion and form synaptic connections has been analyzed in a developing mammalian spinal cord in vitro. After isolation of the entire central nervous system (CNS) of the newly born South American opossum (Monodelphis domestica) the spinal cord was crushed. Outgrowth through and beyond the lesion was observed in living preparations for 2-5 days by staining axons with carbocyanine dyes. The structure of the acute crush and the growing neurites was examined by light and electron microscopy in tissue fixed immediately after the crush had been made. All axons had been severed and the site was filled with debris and amorphous vesicular structures. By 3 days after injury, numerous labelled neurites had grown into the lesion; by 4 days, many had extended several millimetres beyond it. At this time normal axonal profiles were apparent in electron micrographs of the crush site. Although fewer axons grew across the lesion than had been severed by the crush, the amplitudes of compound action potential volleys conducted across the crush in injured preparations were comparable with those recorded from uninjured spinal cords. Physiological experiments made with raised concentrations of extracellular magnesium in the culture fluid indicated that growing axons had formed synaptic connections. Thus, delayed major peaks of the response were abolished while the small component corresponding to through conduction remained unaffected by magnesium. These experiments demonstrate the development of synaptic interactions by the growing neurites and confirm the far greater powers of repair in neonatal mammals compared to adults. They set the stage for comparing molecular mechanisms involved in development and regeneration of the mammalian CNS.
Mots-clé
Action Potentials Animals Animals, Newborn Axons/*physiology Carbocyanines Culture Techniques Electrophysiology Fluorescent Dyes Magnesium/pharmacology Microscopy, Electron Nerve Crush *Opossums Spinal Cord/ultrastructure Spinal Cord Injuries/*pathology/physiopathology Synapses/physiology/ultrastructure
Pubmed
Web of science
Création de la notice
24/01/2008 15:26
Dernière modification de la notice
20/08/2019 14:21
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