scholarly journals THE STRUCTURE AND CONCENTRATION OF SOLIDS IN PHOTORECEPTOR CELLS STUDIED BY REFRACTOMETRY AND INTERFERENCE MICROSCOPY

1957 ◽  
Vol 3 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Richard L. Sidman
Keyword(s):  
Photoreceptor Cells ◽  
Interference Microscopy ◽  
Refractive Indices ◽  
Rod Outer Segments ◽  
Vertebrate Species ◽  
Rods And Cones ◽  
Outer Segments ◽  
Retinal Rods ◽  
Cone Cells ◽  
Longitudinal Fiber

Fragments of freshly obtained retinas of several vertebrate species were studied by refractometry, with reference to the structure of the rods and cones. The findings allowed a reassessment of previous descriptions based mainly on fixed material. The refractometric method was used also to measure the refractice indices and to calculate the concentrations of solids and water in the various cell segments. The main quantitative data were confirmed by interference microscopy. When examined by the method of refractometry the outer segments of freshly prepared retinal rods appear homogeneous. Within a few minutes a single eccentric longitudinal fiber appears, and transverse striations may develop. These changes are attributed to imbibition of water and swelling in structures normally too small for detection by light microscopy. The central "core" of outer segments and the chromophobic disc between outer and inner segments appear to be artifacts resulting from shrinkage during dehydration. The fresh outer segments of cones, and the inner segments of rods and cones also are described and illustrated. The volumes, refractive indices, concentrations of solids, and wet and dry weights of various segments of the photoreceptor cells were tabulated. Rod outer segments of the different species vary more than 100-fold in volume and mass but all have concentrations of solids of 40 to 43 per cent. Cone outer segments contain only about 30 per cent solids. The myoids, paraboloids, and ellipsoids of the inner segments likewise have characteristic refractive indices and concentrations of solids. Some of the limitations and particular virtues of refractometry as a method for quantitative analysis of living cells are discussed in comparison with more conventional biochemical techniques. Also the shapes and refractive indices of the various segments of photoreceptor cells are considered in relation to the absorption and transmission of light. The Stiles-Crawford effect can be accounted for on the basis of the structure of cone cells.

scholarly journals FINE STRUCTURE OF THE PINEAL ORGANS OF THE ADULT FROG, RANA PIPIENS

1964 ◽  
Vol 22 (3) ◽  
pp. 653-674 ◽  
Author(s):  
Douglas E. Kelly ◽  
Stuart W. Smith
Keyword(s):  
Rana Pipiens ◽  
Photoreceptor Cells ◽  
Rods And Cones ◽  
Adult Frog ◽  
Outer Segments ◽  
Lateral Eye ◽  
Retinal Photoreceptors ◽  
Retinal Rods ◽  
Cytological Features ◽  
Pineal Photoreceptors

Frontal organs and epiphyses of the pineal system from the adult frog, Rana pipiens, were fixed in s-collidine-buffered osmium tetroxide, embedded in Epon 812, and examined by electron microscopy. Epiphyseal material was also fixed in a variety of ways and subjected to a series of cytochemical tests for light microscopy. An ultrastructure resembling that of lateral eye retina is confirmed in this species. Photoreceptor cells of the epiphysis and frontal organ display many cytological features similar to those of retinal rods and cones in the arrangement of their outer and inner segments and synaptic components. However, in these pineal organs the outer segments are disoriented relative to each other and may display a disarranged internal organization unlike normal retinal photoreceptors. Furthermore, other pineal outer segments often appear degenerate. Since immature stages in the development of new outer segments also appear to be present, adult pineal photoreceptors are probably engaged in a constant renewal of outer segment membranes. The evidence further suggests that macrophages are involved in phagocytosis of degenerated outer segments. Postulated photoreceptor activities and the possibility of secondary pineal functions, such as secretion, are discussed in view of current morphological and cytochemical findings.

scholarly journals INHERITED RETINAL DYSTROPHY IN THE RAT

1962 ◽  
Vol 14 (1) ◽  
pp. 73-109 ◽  
Author(s):  
John E. Dowling ◽  
Richard L. Sidman
Keyword(s):  
Pigment Epithelium ◽  
Light And Electron Microscopy ◽  
Retinal Dystrophy ◽  
Photoreceptor Cells ◽  
Pigment Cells ◽  
Membrane Thickness ◽  
Outer Segments ◽  
Progressive Loss ◽  
Retinal Rods ◽  
Microscopy Data

Retinal dystrophies, known in man, dog, mouse, and rat, involve progressive loss of photoreceptor cells with onset during or soon after the developmental period. Functional (electroretinogram), chemical (rhodopsin analyses) and morphological (light and electron microscopy) data obtained in the rat indicated two main processes: (a) overproduction of rhodopsin and an associated abnormal lamellar tissue component, (b) progressive loss of photoreceptor cells. The first abnormality recognized was the appearance of swirling sheets or bundles of extracellular lamellae between normally developing retinal rods and pigment epithelium; membrane thickness and spacing resembled that in normal outer segments. Rhodopsin content reached twice normal values, was present in both rods and extracellular lamellae, and was qualitatively normal, judged by absorption maximum and products of bleaching. Photoreceptors attained virtually adult form and ERG function. Then rod inner segments and nuclei began degenerating; the ERG lost sensitivity and showed selective depression of the a-wave at high luminances. Outer segments and lamellae gradually degenerated and rhodopsin content decreased. No phagocytosis was seen, though pigment cells partially dedifferentiated and many migrated through the outer segment-debris zone toward the retina. Eventually photoreceptor cells and the b-wave of the ERG entirely disappeared. Rats kept in darkness retained electrical activity, rhodopsin content, rod structure, and extracellular lamellae longer than litter mates in light.

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.

scholarly journals Immunocytochemical localization of opsin in outer segments and Golgi zones of frog photoreceptor cells. An electron microscope analysis of cross-linked albumin-embedded retinas

1978 ◽  
Vol 77 (1) ◽  
pp. 196-210 ◽  
Author(s):  
DS Papermaster ◽  
BG Schneider ◽  
MA Zorn ◽  
JP Kraehenbuhl
Keyword(s):  
Electron Microscope ◽  
Outer Segment ◽  
Specific Binding ◽  
Photoreceptor Cells ◽  
Indirect Detection ◽  
Thin Sections ◽  
Rods And Cones ◽  
Outer Segments ◽  
Cell Structures ◽  
Cone Photopigments

Adult vertebrate retinal cells (rod and cones) continuously synthesize membrane proteins and transport them to the organelle specialized for photon capture, the outer segment. The cell structures involved in the synthesis of opsin have been identified by means of immunocytochemistry at the electron microscope level. Two indirect detection systems were used: (a) rabbit antibodies to frog opsin were localized with ferritin conjugated F(ab')2 of sheep antibodies to rabbit F(ab')2 and (b) sheep antibodies to cattle opsin were coupled to biotin and visualized by means of avidin-ferritin conjugates (AvF). The reagents were applied directly to the surface of thin sections of frog retinal tissues embedded in glutaraldehyde cross-linked bovine serum albumin (BSA). Specific binding of anti-opsin antibodies indicates that opsin is localized in the disks of rod outer segments (ROS), as expected, and in the Golgi zone of the rod cell inner segments. In addition, we observed quantitatively different labeling patterns of outer segments of rods and cones with each of the sera employed. These reactions may indicate immunological homology of rod and cone photopigments. Because these quantitiative variations of labeling density extend along the entire length of the outer segment, they also serve to identify the cell which has shed its disks into adjacent pigment ipithelial cell phagosomes.

Changes in Structure of the Disks of Retinal Rods in Hypotonic Solutions

1973 ◽  
Vol 13 (3) ◽  
pp. 787-797
Author(s):  
GERTRUDE FALK ◽  
P. FATT
Keyword(s):  
Electron Microscopy ◽  
Cross Sections ◽  
Light And Electron Microscopy ◽  
Ringer Solution ◽  
Rod Outer Segments ◽  
Outer Segments ◽  
Retinal Rods

Changes in isolated frog rod outer segments, suspended in hypotonic solutions, have been examined by light and electron microscopy. Swelling of the disk occurs in hypotonic solutions. When one half or more NaCl is omitted from the Ringer solution used for suspending the rod outer segments, swelling is accompanied by the appearance of localized, irregular expansions projecting as buds from the disks. The axes of the buds tend to be in the plane of the disk, as can be seen in cross-sections of outer segments. In longitudinal sections of outer segments, the sectioned buds have profiles which were previously interpreted as vesicles. Attention is drawn to the properties of the disk edge, among which is a resistance to extension.

scholarly journals Localization of peripherin/rds in the disk membranes of cone and rod photoreceptors: relationship to disk membrane morphogenesis and retinal degeneration.

1992 ◽  
Vol 116 (3) ◽  
pp. 659-667 ◽  
Author(s):  
K Arikawa ◽  
L L Molday ◽  
R S Molday ◽  
D S Williams
Keyword(s):  
Plasma Membrane ◽  
Retinal Degeneration ◽  
Outer Segment ◽  
Photoreceptor Cells ◽  
Growth Stages ◽  
Rod Outer Segments ◽  
Rod Photoreceptor ◽  
Outer Segments ◽  
Disk Membrane ◽  
Membrane Morphogenesis

The outer segments of vertebrate rod photoreceptor cells consist of an ordered stack of membrane disks, which, except for a few nascent disks at the base of the outer segment, is surrounded by a separate plasma membrane. Previous studies indicate that the protein, peripherin or peripherin/rds, is localized along the rim of mature disks of rod outer segments. A mutation in the gene for this protein has been reported to be responsible for retinal degeneration in the rds mouse. In the present study, we have shown by immunogold labeling of rat and ground squirrel retinas that peripherin/rds is present in the disk rims of cone outer segments as well as rod outer segments. Additionally, in the basal regions of rod and cone outer segments, where disk morphogenesis occurs, we have found that the distribution of peripherin/rds is restricted to a region that is adjacent to the cilium. Extension of its distribution from the cilium coincides with the formation of the disk rim. These results support the model of disk membrane morphogenesis that predicts rim formation to be a second stage of growth, after the first stage in which the ciliary plasma membrane evaginates to form open nascent disks. The results also indicate how the proteins of the outer segment plasma membrane and the disk membranes are sorted into their separate domains: different sets of proteins may be incorporated into membrane outgrowths during different growth stages of disk morphogenesis. Finally, the presence of peripherin/rds protein in both cone and rod outer segment disks, together with the phenotype of the rds mouse, which is characterized by the failure of both rod and cone outer segment formation, suggest that the same rds gene is expressed in both types of photoreceptor cells.

Changes in length and disk shedding rate of Xenopus rod outer segments associated with metamorphosis

1978 ◽  
Vol 201 (1143) ◽  
pp. 169-177 ◽  
Keyword(s):  
Histological Examination ◽  
Pigment Epithelium ◽  
Large Change ◽  
Rod Outer Segments ◽  
Cellular Organization ◽  
Dramatic Decrease ◽  
Scotopic Sensitivity ◽  
Rods And Cones ◽  
Outer Segments ◽  
Metamorphic Climax

Histological examination of the retinae of Xenopus tadpoles undergoing the extensive transformations of metamorphic climax revealed a progressive and dramatic decrease in the length of rod outer segments (r. o. s.) (by 1.22 µm/day), which was reversed after the completion of metamorphosis, when r. o. s. grew longer (by 1.11 µm/day). The rate of r. o. s. disk addition during these two periods was determined by examining the incorporation of [ 3 H]-leucine by light microscopic autoradiography. The band of labelled protein in r. o. s. was displaced sclerally at a rate of 1.70 µm/day during the first half of metamorphic climax, and of 1.56 µm/day in young juveniles during the second month after metamorphosis. The similarity of the rate of band displacement at these times indicates that the changes in r. o. s. length associated with metamorphosis result from major changes in the rate of disk shedding and/or phagocytosis, which was about 2.92 µm/day pre-metamorphically and 0.45 µm/day post-metamorphically. E. m. observation at these stages and during the final stages of metamorphic climax revealed no significant alterations in the cellular organization or ultrastructure of rods or pigment epithelium, even though some r. o. s. were only 3 µm long. This large change in r. o. s. length undoubtedly influences the animal’s scotopic sensitivity and the relative mesopic activity of its rods and cones, and may have important effects on the animal’s visual physiology.

scholarly journals Correlation of rhodopsin biogenesis with ultrastructural morphogenesis in the chick retina.

1975 ◽  
Vol 64 (1) ◽  
pp. 235-241 ◽  
Author(s):  
W T Mason ◽  
K J Bighouse
Keyword(s):  
Outer Segment ◽  
Receptor Cell ◽  
Rod Outer Segments ◽  
Membrane Biogenesis ◽  
Rod Outer Segment ◽  
Rods And Cones ◽  
Outer Segments ◽  
Chick Retina ◽  
Disk Membrane ◽  
Detergent Extraction

The developing chick retina from stages 39-45 has been examined by biochemical and electron microscope techniques. The levels of rhodopsin contained in the maturing chick retina were evaluated by detergent extraction and correlated with rod outer segment formation. It was found that the appearance of rhodopsin in significant levels preceded outer segment formation by at least 2 days, thus implying that rhodopsin is synthesized in the receptor cell inner segment and translocated to the outer limb when disk membrane biogenesis occurs. The level of rhodopsin continues to rise as the rod outer segment develops. Development of both rods and cones originates and proceeds most rapidly in the fundus or central region and proceeds toward the periphery. In general, rod outer segments were noted to develop far more rapidly than cone outer segments.

scholarly journals Localization of antibody binding sites in ultrathin sections of unembedded frog retinal tissue.

1983 ◽  
Vol 31 (1) ◽  
pp. 29-34 ◽  
Author(s):  
D C Pease ◽  
I Nir ◽  
V Clark ◽  
M Hall
Keyword(s):  
Rabbit Antiserum ◽  
External Support ◽  
Rod Outer Segments ◽  
General Technique ◽  
Rods And Cones ◽  
Retinal Tissue ◽  
Outer Segments ◽  
Frog Retina ◽  
Rabbit Igg ◽  
Ultrathin Sections

Much ultrastructural detail is retained in tissue fixed only with aldehydes and subsequently air-dried after suspension in a polyvinyl acetate emulsion. The latter provides an external support only, but permits ultrathin sectioning; thus, an exposure of intracellular contents for potential immunocytochemical reactions is achieved. Sections of unembedded frog retina so prepared have been studied with success. The tissue was incubated first with a rabbit antiserum prepared against gradient purified bovine rod outer segments. Following incubation, reacted sites were labeled with ferritin-conjugated goat anti-rabbit IgG and stained with phosphotungstic acid. Intense labeling of the rod outer segments was clearly achieved, whereas the cone outer segments were without label. Other parts of the retina, including the ellipsoid region of both rods and cones, were also without significant label. These regions provided an intrinsic control for the specificity of the antiserum and established the validity of the general technique.

Microtubules in a rod-specific cytoskeleton associated with outer segment incisures

2000 ◽  
Vol 17 (5) ◽  
pp. 711-722 ◽  
Author(s):  
MARION SANGSTER ECKMILLER
Keyword(s):  
Plasma Membrane ◽  
Electron Microscopic Examination ◽  
Normal Structure ◽  
Rod Outer Segments ◽  
Electron Microscopic ◽  
Immunofluorescent Localization ◽  
Rods And Cones ◽  
Retinal Degenerations ◽  
Outer Segments ◽  
Tubulin Immunofluorescence

In many vertebrate retinas the outer segments of rod photoreceptors have multiple incisures, that is, there are numerous indentations in the highly curved membrane forming the edge of their disks and in the plasma membrane enclosing the entire stack of disks. Immunofluorescent localization of tubulin in amphibian photoreceptors yielded a novel series of thin, parallel, fluorescent lines in rod outer segments that extended their full length and coincided with their multiple incisures. Electron-microscopic examination of amphibian retinas revealed the structures responsible for this fluorescence: longitudinally oriented microtubules were associated with incisures at heights throughout rod outer segments. These microtubules were located between the disk rims and the overlying plasma membrane, in the small cytoplasmic compartment at the mouth of incisures; the microtubules and membranes were separated from each other by distances that were uniform, as though interconnected by filaments described in other studies. Thus, in amphibian rod outer segments the incisures mark the site of a cytoskeletal system containing longitudinal microtubules distinct from those of the ciliary axoneme, linked by filaments to the adjacent membranes. This cytoskeleton is expected to be important for the normal structure, function, and renewal of rod outer segments. In amphibian cone outer segments, which do not have incisures, the only anti-tubulin immunofluorescence and the only microtubules were at the axoneme. These findings may help elucidate the diverse properties of rods and cones in many vertebrate retinas and could prove relevant for human retinal degenerations.

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