Summary
Pieces of human retinas were dissected from dark adapted eyes enucleated because of malignant tumours. The preparations were perfused at 36°C with a glucose-containing ionic medium of pH 7.4. The rhodopsin content was determined by means of the absorbance changes due to bleaching. Electroretino-graphic responses were recorded transretinally.
Scotopicb-waves (8 preparations) or slow P III responses (19 preparations) were obtained at stimulus strengths corresponding to approx. one quantum absorbed per rod per flash (20 ms). Photopic potentials appeared when the stimuli were 1.5 log units more intense.
Partial bleaching of rhodopsin was followed by an amplitude decrease of scotopic responses. This decrease was a temporary one from which the retinas fully recovered if less than 6% of the rhodopsin had been bleached. Bleaching of larger amounts of the pigment resulted in a permanent loss of potential amplitude and of retinal sensitivity. During the recovery process after small bleaches, the reduction of potential amplitude was proportional to the concentration of metarhodopsin380 in the rods, and may indicate a link between metarhodopsin380 and the temporary desensitization of the retina.
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Bender, S., Baumann, C. Empfindlichkeit und Sehpurpurgehalt der isolierten menschlichen Netzhaut. Pflugers Arch. 341, 219–232 (1973). https://doi.org/10.1007/BF00592791
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DOI: https://doi.org/10.1007/BF00592791