Acute Application of NT-3 on Neonatal Rat Spinal Cords
نویسندگان
چکیده
Neuronal survival, growth and differentiation in the developing brain and spinal cord are dependant upon the presence of specific growth factors called neurotrophins. These include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4/5 and function to regulate neuronal survival and differentiation during the development of the vertebrate nervous system by binding with high affinity to the tyrosine kinase (trk) family of receptors, which includes trkA, trkB and trkC. Neurotrophins can also bind to another receptor type named the p75 receptor of the tumor necrosis family, although binding affinity is rather low. Signaling from this receptor most commonly results in programmed cell death. Neurotrophins may activate trk and p75 receptors individually or simultaneously via complexes known as heterocomplexes. The reason for study of these complexes involves their unique ability to discontinue the apoptotic signaling of p75 . Coupled with the knowledge that trkC interacts exclusively with NT-3, this study aimed at determining whether acute application of NT3 would cause an upregulation of heterocomplexes. This would serve as a mechanism to prevent p75 induced cell death. This is of particular importance in circumstances such as spinal cord injury in which p75 expression is drastically upregulated. It was found that there were no observable differences in the amount of heterocomplex expression between acutely treated neonatal rat spinal cords and control cords, however this project yielded other unexpected yet interesting results. It was noted that labeled heterocomplex tracts possessed an abnormally high number of stained nuclei indicating that these tracts may be highly concentrated on radial glial cells since these are known to serve as guide wires to young, migrating cells.
منابع مشابه
Chronic neurotrophin-3 strengthens synaptic connections to motoneurons in the neonatal rat.
We report that neurotrophin-3 (NT-3), delivered chronically via fibroblasts implanted intrathecally into neonatal rats, can facilitate synaptic transmission in the spinal cord. A small collagen plug containing NT-3-secreting fibroblasts was placed on the exposed dorsal surface of the spinal cord (L1) of 2-d-old rats; controls received beta-galactosidase-secreting fibroblasts. After 6 hr to 12 d...
متن کاملEffects of Biodegradable Polymers on the Rat's Damaged Spinal Cord Neural Membranes
The overall goal of this study was to identify the appropriate biomaterials able to facilitate the regeneration in rat's injured adult spinal cord. Acute damage to axons is manifested as a breach in their membranes, ionexchange distortion across the compromised region, local depolarization and even conduction block. It would be of particular importance to interrupt the progress of events h...
متن کاملNT-3 evokes an LTP-like facilitation of AMPA/kainate receptor-mediated synaptic transmission in the neonatal rat spinal cord.
Neurotrophin-3 (NT-3) is a neurotrophic factor required for survival of muscle spindle afferents during prenatal development. It also acts postsynaptically to enhance the monosynaptic excitatory postsynaptic potential (EPSP) produced by these fibers in motoneurons when applied over a period of weeks to the axotomized muscle nerve in adult cats. Similar increases in the amplitude of the monosyna...
متن کاملMotoneuron-derived neurotrophin-3 is a survival factor for PAX2-expressing spinal interneurons.
Rat spinal cord interneurons undergo programmed cell death shortly after birth. We investigated here whether cell death of interneurons could be regulated by trophic factors produced by motoneurons, one of their main targets. To test this hypothesis, we studied the effect of the selective destruction of motoneurons on the survival of interneurons in organotypic cultures of embryonic rat spinal ...
متن کاملGABA-receptor-independent dorsal root afferents depolarization in the neonatal rat spinal cord.
Dorsal root afferent depolarization and antidromic firing were studied in isolated spinal cords of neonatal rats. Spontaneous firing accompanied by occasional bursts could be recorded from most dorsal roots in the majority of the cords. The afferent bursts were enhanced after elevation of the extracellular potassium concentration ([K+]e) by 1-2 mM. More substantial afferent bursts were produced...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2011