Abstract
BDNF and NT-4 (but not NT-3 or CNTF) significantly enhanced the outgrowth of early embryonic and adult regenerating RGC axons when provided with a supportive substrate in vitro. BDNF and NT-4 treatment transiently increased RGC axon outgrowth from E15 rat retinas but not from retinas at older embryonic ages. The transient effect of BDNF and NT-4 and the inability of the neurotrophins to promote outgrowth from older embryonic retinal explants suggests a time frame of neurotrophin action and that other chemical factors (target-derived or otherwise) may be necessary for the continued maintenance of developing RGC axons. BDNF and NT-4 also enhanced the outgrowth of regenerating axons from adult retinal explants, but appeared to have a more subtle effect on axon outgrowth, in that the growth-promoting effects of BDNF and NT-4 appeared continuous throughout the incubation period. The suppression of RGC axon outgrowth from embryonic and adult retinae cultured in trkB-IgG-containing medium suggests that the response of developing and regenerating axons, to BDNF and NT-4 are likely to occur through trkB signalling.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
Axons / drug effects*
-
Axons / metabolism
-
Axons / ultrastructure*
-
Brain-Derived Neurotrophic Factor / metabolism
-
Brain-Derived Neurotrophic Factor / pharmacology
-
Cell Differentiation / drug effects
-
Cell Differentiation / physiology
-
Ciliary Neurotrophic Factor / metabolism
-
Ciliary Neurotrophic Factor / pharmacology
-
Fetus
-
Growth Cones / drug effects
-
Growth Cones / metabolism
-
Growth Cones / ultrastructure
-
Immunoglobulin G / metabolism
-
Immunoglobulin G / pharmacology
-
Microscopy, Electron
-
Nerve Growth Factors / metabolism
-
Nerve Growth Factors / pharmacology*
-
Nerve Regeneration / drug effects*
-
Nerve Regeneration / physiology
-
Neurotrophin 3 / metabolism
-
Neurotrophin 3 / pharmacology
-
Organ Culture Techniques
-
Rats
-
Receptor, trkB / drug effects
-
Receptor, trkB / metabolism
-
Retina / embryology
-
Retina / growth & development
-
Retina / ultrastructure
-
Retinal Ganglion Cells / drug effects*
-
Retinal Ganglion Cells / metabolism
-
Retinal Ganglion Cells / ultrastructure*
-
Signal Transduction / drug effects
-
Signal Transduction / physiology
Substances
-
Brain-Derived Neurotrophic Factor
-
Ciliary Neurotrophic Factor
-
Immunoglobulin G
-
Nerve Growth Factors
-
Neurotrophin 3
-
Receptor, trkB
-
neurotrophin 4