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Scanning Microscopy Mar 1987Scanning electron microscopy was performed on cell cultures of embryonic and post-hatch chick retinas co-cultured with optic lobe neurons or in medium that had been...
Scanning electron microscopy was performed on cell cultures of embryonic and post-hatch chick retinas co-cultured with optic lobe neurons or in medium that had been pre-conditioned with optic lobe cells. The culture medium consisted of Eagles Basal Medium supplemented with glucose, fetal calf serum, glutamine and bicarbonate. Application of colchicine (5 micrograms/ml) to the cultures, encouraged the dissociation of retinal cell rosettes and optic lobe neuron aggregates, thereby allowing us to examine differentiation of isolated photoreceptor cells. Over time, developing photoreceptor cells gradually took on the morphological characteristics of rods and cones in the post-hatch chick: cells were polarized having a single neurite on one end of the cell and inner and outer segment-like structures on the other end. Developing cone cells elaborated an oil droplet and filopodial-like processes at the apical end of the inner segment. The latter may correspond to the calyceal processes which normally envelop the basal 1/3 of the outer segment. The sequence of events noted in vitro parallel those previously reported in vivo.
Topics: Animals; Cell Aggregation; Cell Differentiation; Cells, Cultured; Chick Embryo; Chickens; Colchicine; Microscopy, Electron, Scanning; Photoreceptor Cells
PubMed: 3589602
DOI: No ID Found -
Acta Anatomica 1983The structure of the photoreceptors of the domestic sheep has been investigated by light and electron microscopy. In the sheep retina the photoreceptors are readily... (Comparative Study)
Comparative Study
The structure of the photoreceptors of the domestic sheep has been investigated by light and electron microscopy. In the sheep retina the photoreceptors are readily differentiated and adequately described by the classical terminology of rods and cones. Rods are more numerous then cones. They appear as tall slender cells measuring 45-50 microns in length and 2-3 microns in diameter with inner and outer segments of the same diameter. Rod nuclei are located at all levels of the outer nuclear layer. The rod synaptic ending is small and rounded with two to three invaginated (ribbon) synaptic sites. Cone cells are shorter than rods, measuring only 30-35 micron in total length. The cone inner segment is wider than the outer segment which tapers distally. Cone nuclei are located adjacent to the external limiting membrane and are more vesicular than rod nuclei. Cone synaptic endings are larger spherules with ten to twelve (ribbon) synaptic sites. Both rods and cones also display superficial synaptic regions. An unusual form of apparent degeneration is noted in cone photoreceptors. This involves a disorganization and loss of the outer segment and a progressive distal movement of the nucleus through the inner segment towards the retinal epithelial layer. The structure and ratio of rods and cones remains similar in both the tapetal and nontapetal regions of the fundus.
Topics: Animals; Nerve Degeneration; Photoreceptor Cells; Retina; Sheep
PubMed: 6880602
DOI: 10.1159/000145750 -
Comparative Biochemistry and... 19891. Properties of median photoreceptor cells in cultured ocelli from the giant barnacle (Balanus nubilus) were compared in isolated ocelli, ocelli maintained with the...
1. Properties of median photoreceptor cells in cultured ocelli from the giant barnacle (Balanus nubilus) were compared in isolated ocelli, ocelli maintained with the supraesophageal ganglion, and fresh ocelli. 2. Cultured photoreceptor cells exhibited slight deterioration after 2-4 weeks. Cell bodies maintained their structure but apparently lost some dendrites. Electron micrographs revealed fewer rhabdomeres. Axons did not degenerate. 3. Intracellularly recorded responses to light in both cultured preparations were qualitatively normal with a small decrease in sensitivity and increase in input resistance. The waveforms of the light responses were normal. 4. The characteristic shadow reflex was maintained after 6 weeks.
Topics: Animals; Cells, Cultured; Photoreceptor Cells; Thoracica
PubMed: 2565793
DOI: 10.1016/0300-9629(89)90587-2 -
Biochemical Society Transactions Nov 1991The biochemical role of the visual-pigment protein, rhodopsin, is reviewed, with reference to vertebrate rods and cones and the microvillar photoreceptors of... (Review)
Review
The biochemical role of the visual-pigment protein, rhodopsin, is reviewed, with reference to vertebrate rods and cones and the microvillar photoreceptors of invertebrates. New results are presented on the structure of squid rhodopsin, which possesses an extensive proline-rich repeat at its C-terminus, using negative-stain electron microscopy.
Topics: Amino Acid Sequence; Animals; Microvilli; Molecular Sequence Data; Photoreceptor Cells; Rhodopsin; Rod Cell Outer Segment; Signal Transduction
PubMed: 1794572
DOI: 10.1042/bst0190858 -
Vision Research Oct 1972
Topics: Animals; Biometry; Diptera; Humans; Light; Optics and Photonics; Photoreceptor Cells; Vision, Ocular
PubMed: 5078794
DOI: 10.1016/0042-6989(72)90045-4 -
Nature: New Biology Nov 1971
Topics: Animals; Anura; Biological Transport, Active; Cell Membrane Permeability; Darkness; Electrophysiology; In Vitro Techniques; Light; Membrane Potentials; Ouabain; Photoreceptor Cells; Sodium; Water-Electrolyte Balance
PubMed: 5286861
DOI: 10.1038/newbio234029a0 -
Vision Research 1986
Review
Topics: Action Potentials; Animals; Fishes; History, 20th Century; Humans; Photoreceptor Cells; Retina; Retinal Ganglion Cells; United States; Vision, Ocular
PubMed: 3303662
DOI: 10.1016/0042-6989(86)90161-6 -
Biochimica Et Biophysica Acta Nov 1973
Review
Topics: Animals; Carbohydrates; Cell Fractionation; Eye Proteins; Lipids; Membranes; Microscopy, Electron; Models, Biological; Phospholipids; Photoreceptor Cells; Retinal Pigments; Species Specificity; Vertebrates
PubMed: 4587475
DOI: 10.1016/0304-4157(73)90006-3 -
Cold Spring Harbor Symposia on... 1990
Review
Topics: Adaptation, Physiological; Amphibians; Animals; Calcium; Cyclic GMP; Kinetics; Models, Neurological; Phosphodiesterase Inhibitors; Photic Stimulation; Photoreceptor Cells
PubMed: 1966770
DOI: 10.1101/sqb.1990.055.01.054 -
Annals of the New York Academy of... Dec 1975Both measurements and rough theoretical calculations suggest that both sites in the plasma membrane where the dark current enters and the mechanism that produces the... (Review)
Review
Both measurements and rough theoretical calculations suggest that both sites in the plasma membrane where the dark current enters and the mechanism that produces the intracellular excitatory transmitter of rod vision operate via ionophoric mechanisms with very low specific conductivities and high ionic specificities properties similar to those of carriers in artificial and natural membranes.
Topics: Animals; Biological Transport; Calcium; Cell Membrane; Ions; Membrane Potentials; Photoreceptor Cells; Structure-Activity Relationship
PubMed: 769641
DOI: 10.1111/j.1749-6632.1975.tb31492.x