The outgrowth response of the axons of developing and regenerating rat retinal ganglion cells in vitro to neurotrophin treatment.
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.
Avwenagha
Ovokeloye
O
Department of Anatomy and Developmental Biology, University College London, Gower Street, WC1E 6BT, London.
Campbell
Gregor
G
Bird
Margaret M
MM
D000818:Animals; D001369:Axons / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure*; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D020934:Ciliary Neurotrophic Factor / Q000378:metabolism / Q000494:pharmacology; D005333:Fetus; D020439:Growth Cones / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D007074:Immunoglobulin G / Q000378:metabolism / Q000494:pharmacology; D008854:Microscopy, Electron; D009414:Nerve Growth Factors / Q000378:metabolism / Q000494:pharmacology*; D009416:Nerve Regeneration / Q000187:drug effects* / Q000502:physiology; D020933:Neurotrophin 3 / Q000378:metabolism / Q000494:pharmacology; D009924:Organ Culture Techniques; D051381:Rats; D020813:Receptor, trkB / Q000187:drug effects / Q000378:metabolism; D012160:Retina / Q000196:embryology / Q000254:growth & development / Q000648:ultrastructure; D012165:Retinal Ganglion Cells / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
D019208:Brain-Derived Neurotrophic Factor; D020934:Ciliary Neurotrophic Factor; D007074:Immunoglobulin G; D009414:Nerve Growth Factors; D020933:Neurotrophin 3; D020813:Receptor, trkB; C073922:neurotrophin 4