Porcine Iris Pigment Epithelial Cells can take up Retinal Outer Segments

1997 ◽  
Vol 65 (2) ◽  
pp. 277-287 ◽  
Author(s):  
ULRICH SCHRAERMEYER ◽  
VOLKER ENZMANN ◽  
LEON KOHEN ◽  
KLAUS ADDICKS ◽  
PETER WIEDEMANN ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Pigment Epithelial ◽  
Outer Segments ◽  
Pigment Epithelial Cells

scholarly journals PHOTORECEPTOR-PIGMENT EPITHELIAL CELL RELATIONSHIPS IN RATS WITH INHERITED RETINAL DEGENERATION

1972 ◽  
Vol 53 (1) ◽  
pp. 185-209 ◽  
Author(s):  
Matthew M. LaVail ◽  
Richard L. Sidman ◽  
Deborah O'Neil
Keyword(s):  
Electron Microscope ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Outer Segment ◽  
Pigment Epithelial ◽  
Outer Segments ◽  
Rcs Rats ◽  
Inherited Retinal Degeneration ◽  
Lamellar Material ◽  
Pigment Epithelial Cells

Protein synthesis and displacement in photoreceptor and pigment epithelial cells of inbred normal (Fisher) and mutant (RCS) rats with inherited retinal degeneration has been studied by light and electron microscope radioautography. Groups of animals 14, 15, 17, 19, 27, 35, and 50 days of age were injected with amino acids-H3 and killed at subsequent time intervals. In normal rats, radioactive protein synthesized in the rod inner segments was incorporated into outer segment saccules and displaced outward; the total renewal time of outer segments at all ages was approximately 9 days. In RCS photoreceptors, outer segment displacement was slowed from the normal rate before day 17 and at all subsequent stages. Most of the newly synthesized protein appeared to migrate only into the basal third of the outer segments. Labeling of pigment epithelial cells in RCS rats was always heavier than in controls. Labeled protein was displaced as early as 1 hr postinjection from pigment epithelial cell somas into the apical processes, and by 2 hr postinjection was located in the adjacent lamellar whorls characteristic of the mutant rat retina. After 1 day, radioactivity was present in the 14, 15, 17, and 19 day series of RCS rats in the apical third of the outer segment layer (occupied mainly by extra lamellar material) while there were few silver grains in the middle third of the layer (occupied mainly by distal parts of outer segments). The RCS pigment epithelial cells thus have an unusual synthetic role and appear to be a source of the extra lamellar material. Electron microscope examination revealed that many intact pigment epithelial cell processes were incorporated into the large whorls of extra lamellae. In addition, many disorganized outer segment saccules were observed in continuity with longer membranous lamellae and large lamellar whorls. The extra lamellar material therefore appears to be derived from both rod outer segments and pigment epithelial cells.

scholarly journals 5′-Nucleotidase in Rat Photoreceptor Cells and Pigment Epithelial Cells Processed by Rapid-freezing Enzyme Cytochemistry

1998 ◽  
Vol 46 (9) ◽  
pp. 1091-1095 ◽  
Author(s):  
Toshihiro Takizawa
Keyword(s):  
Epithelial Cells ◽  
Photoreceptor Cells ◽  
Striking Difference ◽  
Rapid Freezing ◽  
Rod Outer Segments ◽  
Enzyme Cytochemistry ◽  
Apical Process ◽  
Pigment Epithelial ◽  
Outer Segments ◽  
Pigment Epithelial Cells

This report describes the subcellular distribution of 5′-nucleotidase (5′-NT) in rat photoreceptor cells and pigment epithelial cells processed by rapid-freeze enzyme cytochemistry. There was a striking difference in the ultrastructural localization of 5′-NT activity between rod outer segments after freeze-substitution fixation and conventional fixation. By rapid-freezing enzyme cytochemistry, 5′-NT activity was localized in the extradiscal space of intact nonvacuolated discs, whereas by conventional cytochemistry it was shown in the intradiscal space of artifactual vacuolated discs. In the freeze-substituted retinal cells, an appreciable difference in functional 5′-NT molecules was also found. The soluble 5′-NT on the cytoplasmic side of the disc membrane was vital in the rod outer segments, whereas the membrane-bound ecto-5′-NT on the exoplasmic (external) surface of the apical process was active in the pigment epithelial cells. Rapid-freezing enzyme cytochemistry should be worth employing as a method to reveal the fine localization of enzyme activity at the level of cell ultrastructures, which are poorly preserved by conventional fixation, and should provide information approximate to that in living cells.

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