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Grafting of a new target prevents synapse loss in abducens internuclear neurons induced by axotomy.
- Source :
-
Neuroscience [Neuroscience] 2003; Vol. 118 (3), pp. 611-26. - Publication Year :
- 2003
-
Abstract
- The loss of afferent synaptic boutons is a prominent alteration induced by axotomy on adult central neurons. In this work we attempted to prove whether synapse loss could be reverted by reconnection with a new target. We severed the medial longitudinal fascicle of adult cats and then transplanted embryonic cerebellar primordia at the lesion site immediately after lesion. As previously shown, the transected axons from abducens internuclear neurons penetrate and reinnervate the graft [J Comp Neurol 444 (2002) 324]. By immunocytochemistry and electron microscopy we studied the synaptology of abducens internuclear neurons under three conditions: control, axotomy and transplant (2 months of survival time). Semithin sections of the abducens nucleus were immunostained against calretinin, to identify abducens internuclear neurons, and either synaptophysin (SF), to label synaptic terminals, or glial fibrillary acidic protein (GFAP) to detect the astrocytic reaction. Optical and linear density of SF and GFAP immunostaining were measured. Data revealed a significant decrease in the density of SF-labeled terminals with a parallel increase in GFAP-immunoreactive elements after axotomy. On the contrary, in the transplant group, the density of SF-labeled terminals was found similar to control, and the astrocytic reaction induced by lesion was significantly reduced. At the ultrastructural level, synaptic coverage and linear density of boutons were measured around the somata of abducens internuclear neurons. Whereas a significant reduction in both parameters was found after axotomy, cells of the transplant group received a normal density of synaptic endings. The ratio between F- and S-type boutons was found similar in the three groups. Therefore, these findings indicate that the grafting of a new target can prevent the loss of afferent synaptic boutons produced by the axotomy.
- Subjects :
- Abducens Nerve metabolism
Abducens Nerve ultrastructure
Animals
Axotomy
Calbindin 2
Cats
Cell Size physiology
Cell Surface Extensions physiology
Cell Surface Extensions ultrastructure
Cerebellum embryology
Cerebellum transplantation
Glial Fibrillary Acidic Protein metabolism
Gliosis physiopathology
Gliosis prevention & control
Gliosis therapy
Immunohistochemistry
Interneurons ultrastructure
Mesencephalon physiology
Mesencephalon ultrastructure
Microscopy, Electron
Neural Pathways injuries
Neural Pathways surgery
Oculomotor Nerve physiology
Oculomotor Nerve ultrastructure
Pons metabolism
Pons ultrastructure
Presynaptic Terminals ultrastructure
Retrograde Degeneration physiopathology
S100 Calcium Binding Protein G metabolism
Synaptophysin metabolism
Brain Tissue Transplantation methods
Interneurons metabolism
Nerve Regeneration physiology
Presynaptic Terminals metabolism
Retrograde Degeneration prevention & control
Retrograde Degeneration therapy
Stem Cell Transplantation methods
Subjects
Details
- Language :
- English
- ISSN :
- 0306-4522
- Volume :
- 118
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 12710971
- Full Text :
- https://doi.org/10.1016/s0306-4522(03)00003-4