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The rate of disk addition to rod outer segments (ROS) varies widely in Xenopus laevis tadpoles kept in cyclic light (12L:12D). When measured as radioactive band (3H-band) displacement during the 2nd day after injection of [3H]leucine, 75% of the daily increment of displacement occurred during the first 8 h of light. During the same interval, the number of open disks at the ROS base increased more than threefold. During the last 8 h of darkness, 3H-band displacement was undetectable and the number of open disks was reduced. These observations suggest the possibility that disk addition may occur discontinuously. During the 3rd and 4th days after injection of [3H]leucine, maximal displacement of the 3H-band occurred later in the day than on the 2nd day, its movement no longer corresponding to the increase in open disks. This delay in 3H-band displacement may reflect a time delay as a result of propagation of compressive stress in an elastic ROS system. Maximal disk loss from ROS as reflected in counts of phagosomes in the pigment epithelium occurred within 1 h of light exposure, and phagosome counts remained high for 4 h before declining to a low level in darkness. Modified lighting regimes affected the daily rhythms of shedding and disk addition differently, suggesting that control mechanisms for the two processes are not directly coupled. During 3 days in darkness, disk addition was reduced 50% compared to controls (12L:12D), whereas shedding was reduced by about 40%. Although reduced in level, shedding occurred as a free-running circadian rhythm. There was no evidence of rhythmicity of disk addition in darkness. In constant light, the rate of disk addition was not different from controls, but shedding was reduced by about 80% after the 1st day. This resulted in a 21% increase in ROS length. Among animals kept on a 2.5L:21.5D cycle, the rate of disk addition was reduced by 40% while shedding was maintained near control levels, resulting in a slight decrease in ROS length. These observations indicate that normal shedding requires alternating light and darkness, and that the daily rhythm of disk addition is due primarily to daily stimulation by light.
BAIRATI,
THE ULTRASTRUCTURE OF THE PIGMENT EPITHELIUM AND OF THE PHOTORECEPTOR-PIGMENT EPITHELIUM JUNCTION IN THE HUMAN RETINA.
1963, Pubmed
BAIRATI,
THE ULTRASTRUCTURE OF THE PIGMENT EPITHELIUM AND OF THE PHOTORECEPTOR-PIGMENT EPITHELIUM JUNCTION IN THE HUMAN RETINA.
1963,
Pubmed Baker,
Development of hydroxyindole-O-methyl transferase activity in eye and brain of the amphibian, Xenopus laevis.
1965,
Pubmed
,
Xenbase Basinger,
Photoreceptor shedding is initiated by light in the frog retina.
1976,
Pubmed Basinger,
Rhodopsin in the rod outer segment plasma membrane.
1976,
Pubmed Besharse,
Renewal of normal and degenerating photoreceptor outer segments in the Ozark cave salamander.
1976,
Pubmed Besharse,
Photoreceptor outer segments: accelerated membrane renewal in rods after exposure to light.
1977,
Pubmed
,
Xenbase Blaurock,
Structure of frog photoreceptor membranes.
1969,
Pubmed Borovjagin,
An ultrastructural study of the frog retinal rod photreceptor membranes phagocyted by pigment epithelium cells after aldehyde fixations and organic solvents treatments.
1973,
Pubmed Bownds,
Characterization and analysis of frog photoreceptor membranes.
1971,
Pubmed Bridges,
Visual pigment loss after light-induced shedding of rod outer segments.
1976,
Pubmed Cohen,
New evidence supporting the linkage to extracellular space of outer segment saccules of frog cones but not rods.
1968,
Pubmed DROZ,
[ACTION OF LIGHT ON METHIONINE S-35 INCORPORATION AT THE LEVEL OF THE MOUSE RETINA].
1963,
Pubmed Hagins,
The visual process: Excitatory mechanisms in the primary receptor cells.
1972,
Pubmed Hall,
Visual pigment renewal in the mature frog retina.
1968,
Pubmed Hall,
Incorporation of (3H)vitamin A into rhodopsin in light- and dark-adapted frogs.
1974,
Pubmed Heller,
Structure of visual pigments. I. Purification, molecular weight, and composition of bovine visual pigment500.
1968,
Pubmed Ishikawa,
The degradation of the photoreceptor outer segment within the pigment epithelial cell of rat retina.
1970,
Pubmed Jan,
Ultrastructural localization of rhodopsin in the vertebrate retina.
1974,
Pubmed Laties,
Procion yellow: a marker dye for outer segment disc patency and for rod renewal.
1976,
Pubmed LaVail,
Rod outer segment disk shedding in rat retina: relationship to cyclic lighting.
1976,
Pubmed Liebman,
Lateral diffusion of visual pigment in photorecptor disk membranes.
1974,
Pubmed NILSSON,
RECEPTOR CELL OUTER SEGMENT DEVELOPMENT AND ULTRASTRUCTURE OF THE DISK MEMBRANES IN THE RETINA OF THE TADPOLE (RANA PIPIENS).
1964,
Pubmed Papermaster,
Biosynthetic and immunochemical characterization of large protein in frog and cattle rod outer segment membranes.
1976,
Pubmed Poo,
Lateral diffusion of phodopsin in Necturus rods.
1973,
Pubmed Spitznas,
Outer segments of photoreceptors and the retinal pigment epithelium. Interrelationship in the human eye.
1970,
Pubmed Wald,
Molecular basis of visual excitation.
1968,
Pubmed Worthington,
Structure of photoreceptor membranes.
1971,
Pubmed Young,
Participation of the retinal pigment epithelium in the rod outer segment renewal process.
1969,
Pubmed Young,
Visual cells and the concept of renewal.
1976,
Pubmed Young,
The renewal of rod and cone outer segments in the rhesus monkey.
1971,
Pubmed Young,
The renewal of protein in retinal rods and cones.
1968,
Pubmed Young,
The renewal of photoreceptor cell outer segments.
1967,
Pubmed
