The principal objective of the proposed research is to identify and characterize some critical cellular mechanisms controlling the growth of optic nerve fibers and the formation of retinotectal synapses, using a combination of morphological, physiological, and biochemical techniques. The retinotectal system provides a very favorable model for studying the dynamics of neurite growth and synaptic development at the cellular and molecular levels, and we plan a set of comparative studies in vivo and in vitro in teleosts (goldfish) and mammals (rats). There are three major goals. The first is to investigate the dynamics of neurite growth in vitro. We have recently discovered that retinal neurite growth cones generate steady currents across their tips, and grow in the direction of an applied field. We plan to examine the effects of local electrical events on cell-substrate adhesion, growth, and the movement and assembly of membrane macromolecules, using internal reflectance and video-enhanced microscopy. Electrogenesis of growing neurites will be monitored with conventional microelectrode recording methods and by the use of a voltage-- sensitive dye. The second goal is to study the development of retinotectal synapses using quantitative EM morphometric and three-dimensional reconstruction methods in order to correlate structural changes and changes in the distribution of membrane macromolecules seen using freeze-fracture methods, with the development of synaptic transmission. The third goal is to establish optimal homogenous culture condtions, by isolating different cell types, and by establishing a continuous cell line of retinal ganglion cells. These studies will involve the development of specific antibodies to different cell types, the production of which would be of great use in the future as tools for cell identification and separation, as molecular probes for membrane macromolecules, and in providing an animal model for autoimmune retinopathies. These studies embrace an area of research (retinal regeneration) targeted by a recent report of the National Advisory Eye Council as being of special interest.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY001117-14
Application #
3255679
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1979-03-01
Project End
1987-03-31
Budget Start
1986-03-01
Budget End
1987-03-31
Support Year
14
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37203
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Langdon, R B; Freeman, J A (1987) Pharmacology of retinotectal transmission in the goldfish: effects of nicotinic ligands, strychnine, and kynurenic acid. J Neurosci 7:760-73

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