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Titolo:
Response of abducens internuclear neurons to axotomy in the adult cat
Autore:
Pastor, AM; Delgado-Garcia, JM; Martinez-Guijarro, FJ; Lopez-Garcia, C; de la Cruz, RR;
Indirizzi:
Univ Sevilla, Lab Neurociencia, Fac Biol, Seville 41012, Spain Univ Sevilla Seville Spain 41012 ciencia, Fac Biol, Seville 41012, Spain Univ Valencia, Dept Biol Celular, E-46100 Burjassot, Spain Univ Valencia Burjassot Spain E-46100 Celular, E-46100 Burjassot, Spain
Titolo Testata:
JOURNAL OF COMPARATIVE NEUROLOGY
fascicolo: 3, volume: 427, anno: 2000,
pagine: 370 - 390
SICI:
0021-9967(20001120)427:3<370:ROAINT>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
INTER-NUCLEAR NEURONS; NERVE GROWTH-FACTOR; SEPTAL CHOLINERGIC NEURONS; SUPERIOR CERVICAL GANGLION; MAMMALIAN CENTRAL NEURONS; RAT SPINAL-CORD; HORSERADISH-PEROXIDASE; AXONAL REGENERATION; HIPPOCAMPAL-NEURONS; OCULOMOTOR NUCLEUS;
Keywords:
oculomotor system; medial longitudinal fascicle; neuronal injury; sprouting; synaptic detachment; glial reaction;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
85
Recensione:
Indirizzi per estratti:
Indirizzo: de la Cruz, RR Univ Sevilla, Lab Neurociencia, Fac Biol, Avda Reina Mercedes 6, Seville 41012, Spain Univ Sevilla Avda Reina Mercedes 6 Seville Spain 41012 ain
Citazione:
A.M. Pastor et al., "Response of abducens internuclear neurons to axotomy in the adult cat", J COMP NEUR, 427(3), 2000, pp. 370-390

Abstract

The highly specific projection of abducens internuclear neurons on the medial rectus motoneurons of the oculomotor nucleus constitutes an optimal model for investigating the effects of axotomy in the central nervous system. We have analyzed the morphological changes induced by this lesion on both the cell bodies and the transected axons of abducens internuclear neurons inthe adult cat. Axotomy was performed by the transection of the medial longitudinal fascicle. Cell counts of Nissl-stained material and calretinin-immunostained abducens internuclear neurons revealed no cell death by 3 monthspostaxotomy. Ultrastructural examination of these cells at 6, 14, 24, and 90 days postaxotomy showed normal cytological features. However, the surface membrane of axotomized neurons appeared contacted by very few synaptic boutons compared to controls. This change was quantified by measuring the percentage of synaptic coverage of the cell bodies and the linear density of boutons. Both parameters decreased significantly after axotomy, with the lowest values at 90 days postlesion (similar to 70% reduction). We also explored axonal regrowth and the possibility of reinnervation of a new target by means of anterograde labeling with biocytin. At all time intervals analyzed, labeled axons were observed to be interrupted at the caudal limit of the lesion; in no case did they cross the scar tissue to reach the distal part of the tract. Nonetheless, a conspicuous axonal sprouting was present at the caudal aspect of the lesion site. Structures suggestive of axonal growth were found, such as large terminal clubs, from which short filopodium-like branches frequently emerged. Similar findings were obtained after parvalbumin and calretinin immunostaining. At the electron microscopy level, biocytin-labeled boutons originating from the sprouts appeared surrounded by either extracellular space, which was extremely dilated at the lesion site, or by glial processes. The great majority of labeled boutons examined were, thus, devoid of neuronal contact, indicating absence of reinnervation of a newtarget. Altogether, these data indicate that abducens internuclear neuronssurvive axotomy in the adult cat and show some form of axonal regrowth, even in the absence of target connection. (C) 2000 Wiley-Liss, Inc.

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Documento generato il 09/07/20 alle ore 01:39:10