|02-15-2010, 06:27 AM||#1|
Join Date: Sep 2004
Differential regulation of dendritic plasticity by neurotrophins following deafferent
Brain Res. 2010 Feb 6.
Differential regulation of dendritic plasticity by neurotrophins following deafferentation of the adult spinal cord is independent of p75(NTR).
Scott AL, Ramer MS.
Zoology and ICORD (International Collaboration on Repair Discoveries), Blusson Spinal Cord Centre, 818 West 8th Avenue, Vancouver, BC, Canada, V5Z 1M9.
Spontaneous and/or treatment-evoked re-modeling of the CNS following spinal cord injury is a prerequisite for functional recovery. While there has been considerable interest in the role of endogenous neurotrophins in spontaneous plasticity of several populations of spinal axons, the same cannot be said for morphological changes to dendrites. Here, we examined the responses of dendrites in the mouse lateral spinal nucleus (LSN, a site of sensory integration in the dorsolateral white matter) to exogenous and endogenous neurotrophins. We performed a septuple dorsal rhizotomy, which permanently eliminates sensory input to the spinal cord, and stimulates sprouting of spinal axons. While dendrites showed no change in density following injury alone, they sprouted vigorously (a two-fold increase in density) upon addition of exogenous brain-derived neurotrophic factor (BDNF). On the other hand, endogenous nerve growth factor (NGF) severely restricted dendritic sprouting, as TrkA-Fc treatment also roughly doubled the density of dendritic processes in the LSN. Spontaneous, BDNF- and TrkA-Fc mediated sprouting were unaffected by the absence of p75(NTR). Importantly, TrkA-Fc treatment markedly reduced expression of the truncated BDNF receptor TrkBT1 in both p75(+/+) and p75(-/-) mice, which was robustly-upregulated by deafferentation in both genotypes. We propose that the upregulation of TrkBT1 by NGF results in a reduced availability of endogenous BDNF to dendrites. Accordingly, sprouting of serotonergic axons, a BDNF-dependent consequence of dorsal root injury, was significantly enhanced in TrkA-Fc-treated animals. These results suggest that NGF and BDNF signaling differentially regulate dendritic plasticity in the deafferented spinal cord. Copyright © 2009. Published by Elsevier B.V.
“As the cast of villains in SCI is vast and collaborative, so too must be the chorus of hero's that rise to meet them” Ramer et al 2005
|Thread||Thread Starter||Forum||Replies||Last Post|
|Exercise restores levels of neurotrophins and synaptic plasticity following spinal co||Snowman||Exercise & Recovery||0||07-11-2005 03:45 PM|
|Forster (2003). Plasticity in Respiratory Motor Control: Invited Review: Plasticity in the control of breathing following sensory denervation.||Wise Young||SCI (Animal) Research||0||01-20-2003 06:38 PM|
|Novikova, et al. (2002). Differential effects of neurotrophins on neuronal survival and axonal regeneration after spinal cord injury in adult rats.||Wise Young||SCI (Animal) Research||0||10-03-2002 09:46 PM|
|Farina, et al. (2002). Regulation of neurogenesis by neurotrophins in developing spinal sensory ganglia.||Wise Young||Stem Cell Research||0||07-24-2002 10:02 PM|
|Mendell, et al. (2001): Neurotrophins and synaptic plasticity in the mammalian spinal cord||Wise Young||SCI (Animal) Research||0||09-23-2001 04:33 PM|