Abstract

The vascular system of the eye represents a compromise between the needs for efficient supply of nutrients to the intraocular tissues and the requirement of good optics. The solution is adequate in young and healthy individuals but involves great risks for local nutritive problems at higher age and in many diseases affecting the blood vessels. Glaucoma, maculopaties, diabetic retinopathy, and cataracts are a few examples. Inadequate nutrition of the retina, including the intraocular part of the optic nerve, of course may cause cell death. Factors contributing during the critical period when nutrition is inadequate are release of excitatory amino acids and/or influx of excess Ca ions into the cells, which may overstimulate the metabolism. There are reasons to suspect that damage may also be induced by flickering light due to overstimulation of cells. Restituted blood flow after a period with inadequate flow may also introduce a problem; reperfusion of partially ischemic parts of the retina may result in the formation of free radicals with profound effects on cell membranes and enzymes.
The aim of our studies is to elucidate the relative roles of the choroidal and retinal blood vessels in supplying nutrients to the retina and to analyze also the requirements of the retina under different conditions. A modification of Sokoloff's deoxyglucose method is used to identify the conditions that seem to be metabolically stressful for the retina and the optic nerve head and to investigate if they involve an increased risk for the retina under conditions of reduced nutrient supply. High intraocular pressure is one of the factors that tend to damage the retina and optic nerve head. Pharmacological means to reduce the IOP are still inadequate in many cases of glaucoma, which motivates further studies on the control of aqueous humor formation and drainage. An isotope dilution method permitting simultaneous, bilateral, near- continuous determination of aqueous humor flow is used in these studies.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY000475-26
Application #
3255401
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1976-06-30
Project End
1994-11-30
Budget Start
1992-12-01
Budget End
1993-11-30
Support Year
26
Fiscal Year
1993
Total Cost
Indirect Cost

  Institution

Name
Uppsala University
Department
Type
DUNS #
City
Uppsala
State
Country
Sweden
Zip Code
SE-75-1 05

  Publications

Wang, L; Kondo, M; Bill, A (1997) Glucose metabolism in cat outer retina. Effects of light and hyperoxia. Invest Ophthalmol Vis Sci 38:48-55
Hamanaka, T; Thornell, L E; Bill, A (1997) Cytoskeleton and tissue origin in the anterior cynomolgus monkey eye. Jpn J Ophthalmol 41:138-49
Nilsson, S F (1994) PACAP-27 and PACAP-38: vascular effects in the eye and some other tissues in the rabbit. Eur J Pharmacol 253:17-25
Hamanaka, T; Bill, A (1994) Platelet aggregation on the endothelium of Schlemm's canal. Exp Eye Res 59:249-56
Bill, A (1993) Some aspects of aqueous humour drainage. Eye (Lond) 7 ( Pt 1):14-9
Seligsohn, E E; Bill, A (1993) Effects of NG-nitro-L-arginine methyl ester on the cardiovascular system of the anaesthetized rabbit and on the cardiovascular response to thyrotropin-releasing hormone. Br J Pharmacol 109:1219-25
Fuchs, A F; Robinson, F R; Straube, A (1993) Role of the caudal fastigial nucleus in saccade generation. I. Neuronal discharge pattern. J Neurophysiol 70:1723-40
Granstam, E; Wang, L; Bill, A (1993) Vascular effects of endothelin-1 in the cat;modification by indomethacin and L-NAME. Acta Physiol Scand 148:165-76
Maepea, O (1992) Pressures in the anterior ciliary arteries, choroidal veins and choriocapillaris. Exp Eye Res 54:731-6
Maepea, O; Bill, A (1992) Pressures in the juxtacanalicular tissue and Schlemm's canal in monkeys. Exp Eye Res 54:879-83

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