Summary
Tree shrews were sacrificed at various times during a 12 h light-12 h dark cycle and the retinal pigment epithelium (RPE) was examined for phagosomes. Analysis of photoreceptor densities showed that the tree-shrew retina consists of approximately 96% cone photoreceptors. Therefore, phagosomes in the RPE were assumed to be mostly those of cones. A peak in the number of RPE phagosomes was found about one hour after the onset of light. The number of phagosomes/mm RPE during the light cycle varied from 17.02 at the peak to 2.49 ten hours after light onset. During the dark cycle, values ranged from 0.10 to 0.61 phagosomes/mm RPE. Size profiles of phagosomes showed that large phagosomes peak in number 1/2 h after light onset, while smaller sizes peak at about 1 h after light onset. This may indicate that maximal shedding and phagocytotic activity occurs sometime before the peak in the total number of phagosomes is reached. Statistical corrections for phagosome size, section thickness and phagosomal degradation time were applied to the data in order to assess outer segment renewal time for tree shrew cones.
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References
Abercrombie M (1946) Estimation of nuclear population from microtome sections. Anat Rec 94:239–247
Basinger J, Hollyfield JG, Rayborn ME (1977) Turnover of rod photoreceptor outer segments. II Membrane addition and loss in relation to light. J Cell Biol 75:507–527
Cohen AI (1970) Further studies on the question of the patency of saccules in outer segments of vertebrate photoreceptors. Vision Res 10:445–453
Dubin MW (1970) The inner plexiform layer of the vertebrate retina: A quantitative and comparative electron microscopic analysis. J Comp Neurol 140:479–506
Fisher SK, Pfeffer BA, Anderson DH (1983) Both rod and cone disc shedding are related to light onset in the cat. Invest Ophthalmol Vis Sci 24:844–856
Herman KG, Steinberg RH (1982) Phagosome movement and the diurnal pattern of phagocytosis in the tapetal retinal pigment epithelium of the opossum. Invest Ophthalmol Vis Sci 23:277–290
Hollyfield JG, Besharse JC, Rayborn ME (1976) The effect of light on the quantity of phagosomes in the pigment epithelium. Exp Eye Res 23:623–635
LaVail MM (1976) Rod outer segment disc shedding in rat retina: Relationship to cyclic shedding. Science 194:1071–1074
O'Day WT, Young RH (1978) Rhythmic daily shedding of outer segment membranes by visual cells in the goldfish. J Cell Biol 76:593–604
Orzalesi N, Fossarello M, Carta S, Del Fiacco G, Diaz D (1982) Identification and distribution of coated vesicles in the retinal pigment epithelium of man and rabbit. Invest Opthalmol Vis Sci 23:689–696
Rohen JW (1962) ‘Sehorgan’. In: Primatologia 2:1210
Rohen JW, Castenholtz A (1967) Über die Zentralisation der Retina bei Primaten. Folia Primat 5:92–147
Samorajski T, Ordy JM, O'Keefe JR (1966) Structural organization of the retina in the tree shrew (Tupaia glis). J Cell Biol 28:489–504
Tabor GA, Fisher SK, Anderson DH (1980) Rod and cone disc shedding in light-entrained tree squirrels. Exp Eye Res 30:545–557
Tabor GA, Anderson DH, Fisher SK, Hollyfield JG (1982) Circadian rod and cone disc shedding in mammalian retina. In: Hollyfield JG (ed) The structure of the eye (Proceedings of the Fourth International Symposium). Elsevier, Amsterdam, pp 67–73
Tigges J (1963) Untersuchungen über den Farbensinn von Tupaia glis. Z Morphol Anthrop 53:109–123
Young RW (1977a) The daily rhythm of shedding and degradation of cone outer segment membranes in the chick retina. Invest Ophthalmol Vis Sci 17:105–116
Young RW (1977b) The daily rhythm of shedding and degradation of cone outer segment membranes in the lizard retina. J Ultrastruct Res 61:172–185
Young RW, Bok D (1979) Metabolism of the retinal pigment epithelium. In: Zinn KM, Marmor MF (eds) The retinal pigment epithelium. Harvard University Press, Cambridge, Mass, pp 103–403
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Immel, J.H., Fisher, S.K. Cone photoreceptor shedding in the tree shrew (Tupaia belangerii). Cell Tissue Res. 239, 667–675 (1985). https://doi.org/10.1007/BF00219247
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DOI: https://doi.org/10.1007/BF00219247