The research has two long-term objectives: to elucidate the nature and physiological significance of interactions between visual pigment and G-protein in the vertebrate photoreceptor (Project 1); and to identify and characterize reactions that, in the dark-adapting eye, mediate the formation of 11-cis retinoid and the delivery of 11-cis retinal chromophore to opsin (Project 2). The Project 1 experiments, employing isolated retina and ROS preparations of skate and amphibian, will examine specific properties of G and the G-pigment interaction: (a) capacity of the Alpha and Beta subunits of G to bind, in light-dependent manner, to the pigment-containing ROS membranes (to be analyzed by extraction and electrophoretic isolation of G AlphaBeta); (b) capacity for ligand charging of G Alpha (to be analyzed through use of 32P-AAGTP, a photoaffinity probe); and (c) correlation of G binding/activation with state of phosphorylation of opsin, and binding of 48K protein to the ROS membranes. Conditions of irradiation to be used will be employed in parallel electrophysiological experiments, for quantitative comparison of the biochemical data with the behavior of receptor threshold. In related experiments, properties of G will be examined (in rat) following dietary deprivation of vitamin A, a treatment known to depress ERG b-wave sensitivity. Overall, the Project 1 studies are aimed at elucidating the molecular basis of sensitivity control during light/dark adaptation; information obtained may be especially useful for characterizing animal models expressing degeneration and/or abnormal development of the photoreceptors. Project 2: To gain information of the all-trans to 11-cis isomerization, H3-all-trans retinoids will be introduced subretinally into eyecup and intact eye preparations, and the fates of these substances examined after light/dark adaptation. Procedures will involve local injection of fluid containing vs. lacking the test retinoid, followed by sectioning of the tissue, and by extraction and HPLC analysis of retinoid products formed. Related experiments will examine effects, on isomerization and rhodopsin regeneration, of other test substances introduced subretinally, e.g., interstitial retinol-binding protein (IRBP). Beyond immediate significance for vitamin A physiology, the Project 2 studies should provide data (and methodology) of direct interest to others studying interactions between the retina and pigment epithelium.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY005494-06
Application #
3260590
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1983-12-01
Project End
1990-08-31
Budget Start
1988-09-01
Budget End
1989-08-31
Support Year
6
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Illinois at Chicago
Department
Type
Schools of Medicine
DUNS #
121911077
City
Chicago
State
IL
Country
United States
Zip Code
60612
Pawar, Ambarish S; Qtaishat, Nasser M; Little, Deborah M et al. (2008) Recovery of rod photoresponses in ABCR-deficient mice. Invest Ophthalmol Vis Sci 49:2743-55
Qtaishat, Nasser M; Pepperberg, David R (2007) Preservation of retinoid influx into eye tissues of ABCR-deficient mice. Curr Eye Res 32:1073-82
Kang Derwent, Jennifer J; Saszik, Shannon M; Maeda, Hidetaka et al. (2007) Test of the paired-flash electroretinographic method in mice lacking b-waves. Vis Neurosci 24:141-9
Gussin, Helene A; Tomlinson, Ian D; Little, Deborah M et al. (2006) Binding of muscimol-conjugated quantum dots to GABAC receptors. J Am Chem Soc 128:15701-13
Silva, Gabriel A; Pepperberg, David R (2004) Step response of mouse rod photoreceptors modeled in terms of elemental photic signals. IEEE Trans Biomed Eng 51:3-12
Pepperberg, D R; Jin, J; Jones, G J (1994) Modulation of transduction gain in light adaptation of retinal rods. Vis Neurosci 11:53-62
Corson, D W; Cornwall, M C; Pepperberg, D R (1994) Evidence for the prolonged photoactivated lifetime of an analogue visual pigment containing 11-cis 9-desmethylretinal. Vis Neurosci 11:91-8
Okajima, T I; Wiggert, B; Chader, G J et al. (1994) Retinoid processing in retinal pigment epithelium of toad (Bufo marinus). J Biol Chem 269:21983-9
Mangini, N J; Garner, G L; Okajima, T I et al. (1994) Effect of hydroxylamine on the subcellular distribution of arrestin (S-antigen) in rod photoreceptors. Vis Neurosci 11:561-8
Pepperberg, D R; Okajima, T L; Wiggert, B et al. (1993) Interphotoreceptor retinoid-binding protein (IRBP). Molecular biology and physiological role in the visual cycle of rhodopsin. Mol Neurobiol 7:61-85

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