This application describes a study of the morphological and physiological organization of the inner plexiform layer of a mammalian retina in which intracellular responses of the various types of neurons will be directly matched with their morphology and synaptology. The experimental approach include: 1) using the isolated rabbit retina eyecup preparation and intracellular recording techniques to examine the physiology of bipolar, amacrine and ganglion cells; 2) injecting horseradish peroxidase into the physiologically identified cell; 3) making a camera lucida drawing of the injected cell and obtaining a computer graphics reconstruction of its three dimensional geometry; 4) embedding and serial thin-sectioning the stained cell to examine with the electron microscope its connectivity. The study will center upon completing the analysis of the rod pathway through the inner plexiform layer. First, the relative contribution of rod and cone inputs into ganglion cells will be investigated by extracellular recordings with metal electrodes. Secondly, with the outer pipette of a coaxial microelectrode, rod dominated ganglion cells will be localized by extracellular recordings; they will be subsequently penetrated with the inner pipette to examine their intracellular activity and stain them with the ultrastructural tracer. Finally, their connectivity will be studied by three-dimensional computer graphics reconstruction from electron micrographs of serial thin sections. The functional interactions at the synapses between the various neurons inserted along the rod pathway will be investigated by intracellular recordings during the application of an on-channel blocking agent. Studies of this sort which directly correlate anatomy and physiology in a mammalian retina provide crucial information to understand the neuronal network which processes visual information in the human retina.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY003011-11
Application #
3257319
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1979-04-01
Project End
1991-06-30
Budget Start
1989-07-01
Budget End
1991-06-30
Support Year
11
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Harvard University
Department
Type
Schools of Medicine
DUNS #
082359691
City
Boston
State
MA
Country
United States
Zip Code
02115
Zhou, Chengwen; Dacheux, Ramon F (2005) Glycine- and GABA-activated inhibitory currents on axon terminals of rabbit cone bipolar cells. Vis Neurosci 22:759-67
MacNeil, Margaret A; Heussy, John K; Dacheux, Ramon F et al. (2004) The population of bipolar cells in the rabbit retina. J Comp Neurol 472:73-86
Zhou, Chengwen; Dacheux, Ramon F (2004) All amacrine cells in the rabbit retina possess AMPA-, NMDA-, GABA-, and glycine-activated currents. Vis Neurosci 21:181-8
Dacheux, Ramon F; Chimento, Melissa F; Amthor, Franklin R (2003) Synaptic input to the on-off directionally selective ganglion cell in the rabbit retina. J Comp Neurol 456:267-78
Rotolo, Thomas C; Dacheux, Ramon F (2003) Evidence for glycine, GABAA, and GABAB receptors on rabbit OFF-alpha ganglion cells. Vis Neurosci 20:285-96
Rotolo, Thomas C; Dacheux, Ramon F (2003) Two neuropharmacological types of rabbit ON-alpha ganglion cells express GABAC receptors. Vis Neurosci 20:373-84
Bloomfield, S A; Dacheux, R F (2001) Rod vision: pathways and processing in the mammalian retina. Prog Retin Eye Res 20:351-84
McGillem, G S; Dacheux, R F (2001) Rabbit cone bipolar cells: correlation of their morphologies with whole-cell recordings. Vis Neurosci 18:675-85
McGillem, G S; Rotolo, T C; Dacheux, R F (2000) GABA responses of rod bipolar cells in rabbit retinal slices. Vis Neurosci 17:381-9
Hu, E H; Dacheux, R F; Bloomfield, S A (2000) A flattened retina-eyecup preparation suitable for electrophysiological studies of neurons visualized with trans-scleral infrared illumination. J Neurosci Methods 103:209-16

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