caa a22 4500 465777090 CHVBK 20180323111945.0 cr unu---uuuuu 170327e19900101xx s 000 0 eng 10.1007/BF02764308 doi (NATIONALLICENCE)springer-10.1007/BF02764308 Diffusion of O2 in normal and ischemic retinas of anesthetized miniature pigs in normoxia and hyperoxia [Elektronische Daten] [Constantin Pournaras, Marcos Tsacopoulos, Charles Riva, André Roth] TransretinalPO2 profiles were recorded with O2-sensitive microelectrodes in the normal retina and in ischemic retinal foci induced by the occlusion of a retinal branch vein with argon laser photocoagulation in anesthetized miniature pigs. In the normal retina there are twoPO2 gradients: one from the inner retina and the other from the choroid, both directed toward the middle of the retina. BothPO2 gradients persisted during hyperoxia. Thus, even in hyperoxia, the choroid does not supply the whole thickness of the normal retina with O2. Preretinal and transretinalPO2 measurements in ischemic inner retinal foci showed the existence of twoPO2 gradients in steady-state systemic normoxia, as did those in the normal retina. This finding indicates that even in ischemia the choroid does not supply O2 to the inner retina; as a result, tissue hypoxia is maintained. During systemic hyperoxia, the intraretinalPO2 measurements in the ischemic foci showed only one gradient going from the choroid toward the inner retina. This gradient indicates that under these conditions, the choroid can supply O2 to the entire thickness of the ischemic retina. Extending a previously formulated hypothesis, we propose that in the ischemic retina as opposed to the normal retina, hyperoxia does not induce an increase in the O2 consumption of the outer retina. This suggestion could explain the rise inPO2 in the inner ischemic retina during hyperoxia. Springer-Verlag, 1990 Pournaras Constantin University Eye Clinic and Experimental Ophthalmology Laboratory, 22, rue Alcide Jentzer, CH-1221, Geneva 4, Switzerland aut Tsacopoulos Marcos University Eye Clinic and Experimental Ophthalmology Laboratory, 22, rue Alcide Jentzer, CH-1221, Geneva 4, Switzerland aut Riva Charles Department of Ophthalmology, University of Pennsylvania and Scheie Eye Institute, Philadelphia, PA, USA aut Roth André University Eye Clinic and Experimental Ophthalmology Laboratory, 22, rue Alcide Jentzer, CH-1221, Geneva 4, Switzerland aut Graefe's Archive for Clinical and Experimental Ophthalmology Springer-Verlag 228/1(1990-01-01), 138-142 0721-832X 228:1<138 1990 228 417 https://doi.org/10.1007/BF02764308 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02764308 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Pournaras Constantin University Eye Clinic and Experimental Ophthalmology Laboratory, 22, rue Alcide Jentzer, CH-1221, Geneva 4, Switzerland aut NATIONALLICENCE 700 1- Tsacopoulos Marcos University Eye Clinic and Experimental Ophthalmology Laboratory, 22, rue Alcide Jentzer, CH-1221, Geneva 4, Switzerland aut NATIONALLICENCE 700 1- Riva Charles Department of Ophthalmology, University of Pennsylvania and Scheie Eye Institute, Philadelphia, PA, USA aut NATIONALLICENCE 700 1- Roth André University Eye Clinic and Experimental Ophthalmology Laboratory, 22, rue Alcide Jentzer, CH-1221, Geneva 4, Switzerland aut NATIONALLICENCE 773 0- Graefe's Archive for Clinical and Experimental Ophthalmology Springer-Verlag 228/1(1990-01-01), 138-142 0721-832X 228:1<138 1990 228 417 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 465777090 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer