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Neurotrophins in the developing and regenerating visual system
C.S. von Bartheld
Department of Physiology and Biophysics, University of
Washington, Seattle, Washington, USA
Offprint requests to: Dr. Christopher
S. von Bartheld, Department of Physiology and Cell Biology, University of
Nevada School of Medicine /352,Reno, NV 89557, USA
Summary. The neurotrophins
NGF, BDNF, NT-3 and NT-4 have a wide range of effects in the development
and regeneration of neural circuits in the visual system of vertebrates.
This review focuses on the localization and functions of neurotrophins in
the retina, lateral geniculate nucleus, suprachiasmatic nucleus, superior
colliculus/optic tectum, and isthmic nuclei. Research of the past 20 years
has shown that neurotrophins and their receptors are localized in numerous
visual centers from the retina to the visual cortex, and that neurotrophins
influence proliferation, neurite outgrowth and survival of cells in the
visual system in vitro and in vivo. A relationship between electrical activity
and neurotrophic functions has been established in several visual centers
in the CNS, and neurotrophins have been implicated in synaptic plasticity
in the visual cortex. Besides functions of neurotrophins as retrograde,
target-derived trophic factors, recent data indicate that neurotrophins
may have anterograde, afferent as well as local, paracrine actions in the
retina, optic nerve and the visual cortex. Some neurotrophins appear to
regulate proliferation and survival of glial cells in the optic pathways.
Neuro-trophins increase the survival of retinal ganglion cells after axotomy
or ischemia and they promote the regeneration of retinal ganglion cell axons
in some vertebrates. Neurotrophins also rescue photoreceptors from degeneration.
These findings implicate the neurotrophins not only as important regulators
during development, but also as potential therapeutic agents in degenerative
retinal diseases and after optic nerve injury. Histol Histopathol 13,
437-459 (1998)
Key words: Retina, NGF, BDNF,
NT-3, Optic nerve
DOI: 10.14670/HH-13.437
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