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      Effects of light and darkness on oxygen distribution and consumption in the cat retina

      research-article
      The Journal of General Physiology
      The Rockefeller University Press

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          Abstract

          These experiments were done to investigate the effects of light and darkness on the oxygenation of the retina in anesthetized cats. Measurements were made with double-barreled oxygen microelectrodes capable of recording both oxygen tension (PO2) and local voltages. Diffuse white illumination presented to a dark-adapted retina led to an increase in PO2 of up to 30 mmHg in the outer half of the retina. Changes were maximal at approximately 75% depth, corresponding to the outer nuclear layer. No change or decrease in PO2 was observed in the inner retina. Light-evoked increases in outer retinal PO2 were graded with the duration and strength of illumination, and were maximal in response to 60 s of illumination at rod saturation. For these stimuli, the increase at the onset of illumination was slower (average half- time, 12.2 s) than the recovery at the end of illumination (average half-time, 5.9 s), but for stimuli above rod saturation, PO2 recovered much more slowly. The profile of PO2 was measured during electrode penetration and withdrawal and during light and dark adaptation. Dark- adapted profiles were characterized by a minimum PO2 of nearly 0 mmHg at depths of 65-85%, and a steep gradient from the minimum to the choroid. During light adaptation at rod saturation, PO2 was elevated in the outer half of the retina and the minimum was eliminated. Fits of the profiles to a one-dimensional model of oxygen diffusion indicated that light reduced the oxygen consumption of the outer retina to approximately 50% of its dark-adapted value.

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          Author and article information

          Journal
          J Gen Physiol
          The Journal of General Physiology
          The Rockefeller University Press
          0022-1295
          1540-7748
          1 October 1986
          : 88
          : 4
          : 521-542
          Article
          87059746
          10.1085/jgp.88.4.521
          2228847
          3783124
          5b795c49-7413-4ba6-a956-1a9db60321fc
          History
          Categories
          Articles

          Anatomy & Physiology
          Anatomy & Physiology

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