Anterograde transport and trophic actions of BDNF and NT-4/5 in the developing rat visual system.
During development the viability of immature neurons may depend upon retrograde, anterograde, or paracrine trophic support. Using (125)I-labeled peptides we show that there is substantial and rapid anterograde transport of brain-derived neurotrophic factor (BDNF) and, to a lesser extent, neurotrophin-4/5 (NT-4/5) to central visual target areas in the neonatal rat brain. Six hours after unilateral intraocular injection, all retinorecipient regions in the thalamus and midbrain are heavily labeled. Intraocular application of physiologically relevant doses of neurotrophin has a marked effect on cells in the developing superior colliculus (SC): 24 h postinjection of BDNF or NT-4/5, the number of pyknotic profiles in the contralateral superficial SC significantly decreases, while total cell numbers increase relative to ipsilateral SC. This increase is primarily associated with neurons. The data support the hypothesis that BDNF and NT-4/5 are anterograde survival factors for postsynaptic cells in the developing rat SC.
Spalding
Kirsty L
KL
School of Anatomy and Human Biology, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia. kirsty.spalding@cmb.ki.se
Tan
Margaret M L
MM
Hendry
Ian A
IA
Harvey
Alan R
AR
D000818:Animals; D000831:Animals, Newborn; D001370:Axonal Transport / Q000502:physiology*; D001921:Brain / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism* / Q000494:pharmacology; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology*; D004396:Coloring Agents; D007457:Iodine Radioisotopes; D051379:Mice; D008807:Mice, Inbred BALB C; D009414:Nerve Growth Factors / Q000378:metabolism* / Q000494:pharmacology; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013477:Superior Colliculi / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D014795:Visual Pathways / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism
D019208:Brain-Derived Neurotrophic Factor; D004396:Coloring Agents; D007457:Iodine Radioisotopes; D009414:Nerve Growth Factors; C073922:neurotrophin 4