caa a22 4500 465778224 CHVBK 20180323111948.0 cr unu---uuuuu 170327e19900301xx s 000 0 eng 10.1007/BF00935724 doi (NATIONALLICENCE)springer-10.1007/BF00935724 Linsenmeier Robert Biomedical Engineering Department and Department of Neurobiology and Physiology, Northwestern University, 2145 Sheridan Road, 60208, Evanston, IL, USA aut Electrophysiological consequences of retinal hypoxia [Elektronische Daten] [Robert Linsenmeier] Experiments on cats show that electrical activity of the inner (proximal) retina is unaffected during systemic hypoxia as long as arterial oxygen tension (PaO2) is above 40 mm Hg. This is due to effective regulation of inner retinal tissue PO2 by the retinal circulation. In contrast, some electrical signals generated in the outer (distal) retina begin to change when PaO2 falls below 70-80 mmHg. The outer retinal responses are generated by the retinal pigment epithelium, but their susceptibility to hypoxia results primarily from their dependence on photoreceptors. Photoreceptor metabolism is sensitive to hypoxia because of the high oxygen consumption of photoreceptors and their reliance on the choroidal circulation, which cannot regulate PO2 in the outer retina. Retinal electrophysiology and oxygen distribution are altered by acutely elevated intraocular pressure just as by hypoxia. These results raise the question as to how inner retinal function can be preserved when outer retinal function is altered. The explanations proposed relate to (1) differences in conditions of light adaptation in different studies, (2) the possible inappropriateness of the previous measurements in the inner retina for revealing photoreceptor dysfunction, and (3) a possible preservation of photoreceptor electrical responses when their metabolism is altered. Comparison of cat and human studies suggests that the human retina is affected in much the same way during hypoxia as the cat retina, but further experiments are required for an understanding of the role of hypoxia in human disease. Springer-Verlag, 1990 Graefe's Archive for Clinical and Experimental Ophthalmology Springer-Verlag 228/2(1990-03-01), 143-150 0721-832X 228:2<143 1990 228 417 https://doi.org/10.1007/BF00935724 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00935724 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Linsenmeier Robert Biomedical Engineering Department and Department of Neurobiology and Physiology, Northwestern University, 2145 Sheridan Road, 60208, Evanston, IL, USA aut NATIONALLICENCE 773 0- Graefe's Archive for Clinical and Experimental Ophthalmology Springer-Verlag 228/2(1990-03-01), 143-150 0721-832X 228:2<143 1990 228 417 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 465777260 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer