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Cell and Tissue Research Jun 1974
Topics: Animals; Axons; Cnidaria; Electrophysiology; Light; Microscopy, Electron; Photoreceptor Cells
PubMed: 4154146
DOI: 10.1007/BF00226774 -
Investigative Ophthalmology & Visual... Mar 1994
Topics: Aging; Cell Count; Humans; Photoreceptor Cells
PubMed: 8125739
DOI: No ID Found -
Nature Methods Dec 2018
Topics: Humans; Light; Opsins; Optogenetics; Photoreceptor Cells
PubMed: 30504884
DOI: 10.1038/s41592-018-0244-3 -
Journal of Photochemistry and... Nov 1990The photoreceptor cells of invertebrate animals differ from those of vertebrates in morphology and physiology. Our present knowledge of the different structures and... (Comparative Study)
Comparative Study Review
The photoreceptor cells of invertebrate animals differ from those of vertebrates in morphology and physiology. Our present knowledge of the different structures and transduction mechanisms of the two animal groups is described. In invertebrates, rhodopsin is converted by light into a meta-rhodopsin which is thermally stable and is usually re-isomerized by light. In contrast, photoisomerization in vertebrates leads to dissociation of the chromophore from opsin, and a metabolic process is necessary to regenerate rhodopsin. The electrical signals of visual excitation have opposite character in vertebrates and invertebrates: the vertebrate photoreceptor cell is hyperpolarized because of a decrease in conductance and invertebrate photoreceptors are depolarized owing to an increase in conductance. Single-photon-evoked excitatory events, which are believed to be a result of concerted action (the opening in invertebrates and the closing in vertebrates) of many light-modulated cation channels, are very different in terms of size and time course of photoreceptors for invertebrates and vertebrates. In invertebrates, the single-photon events (bumps) produced under identical conditions vary greatly in delay (latency), time course and size. The multiphoton response to brighter stimuli is several times as long as a response evoked by a single photon. The single-photon response of vertebrates has a standard size, a standard latency and a standard time course, all three parameters showing relatively small variations. Responses to flashes containing several photons have a shape and time scale that are similar to the single-photon-evoked events, varying only by an amplitude scaling factor, but not in latency and time course. In both vertebrate and invertebrate photoreceptors the single-photon-evoked events become smaller (in size) and faster owing to light adaptation. Calcium is mainly involved in these adaptation phenomena. All light adaptation in vertebrates is primarily, or perhaps exclusively, attributable to calcium feedback. In invertebrates, cyclic AMP (cAMP) is apparently another controller of sensitivity in dark adaptation. The interaction of photoexcited rhodopsin with a G-protein is similar in both vertebrate and invertebrate photoreceptors. However, these G-proteins activate different photoreceptor enzymes (phosphodiesterases): phospholipase C in invertebrates and cGMP phosphodiesterase in vertebrates. In the photoreceptors of vertebrates light leads to a rapid hydrolysis of cGMP which results in closing of cation channels. At present, the identity of the internal terminal messenger in invertebrate photoreceptors is still unsolved.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Amino Acid Sequence; Animals; Electrophysiology; Eye Proteins; Invertebrates; Molecular Sequence Data; Photochemistry; Photoreceptor Cells; Rod Opsins; Vertebrates
PubMed: 2150859
DOI: 10.1016/1011-1344(90)85151-l -
Proceedings of the National Academy of... Nov 1996Application of exogenous retinoic acid (RA) to zebrafish during the initial stages of photoreceptor differentiation results in a precocious development of rod...
Application of exogenous retinoic acid (RA) to zebrafish during the initial stages of photoreceptor differentiation results in a precocious development of rod photoreceptors and an inhibition of cone photoreceptor maturation. The acceleration of rod differentiation is observed initially within the ventral retina 3 days after fertilization, following 24 hr of RA application, and within the dorsal retina 4 days after fertilization, following 48 hr of RA application. The differentiation of rods was impeded significantly when the synthesis of endogenous retinoic acid was inhibited by citral prior to the initial stage of rod differentiation. RA-treated embryos labeled for bromodeoxyuridine (BrdU) uptake revealed that RA exerts its effect on a postmitotic cell population within the developing retina. During normal development in zebrafish, rod differentiation is most robust within the ventral retina, a region previously shown to be rich in RA. Our data suggest that the RA signaling pathway is involved in the differentiation and maturation of both the rod and cone photoreceptors within the developing zebrafish retina.
Topics: Animals; Cell Division; Embryo, Nonmammalian; Immunohistochemistry; Photoreceptor Cells; Reference Values; Retinal Cone Photoreceptor Cells; Retinal Rod Photoreceptor Cells; Rod Opsins; Transcription, Genetic; Tretinoin; Zebrafish
PubMed: 8917585
DOI: 10.1073/pnas.93.23.13298 -
Experimental Eye Research Nov 2013Intact eyes of frog and mouse were studied by X-ray diffraction. Light-induced changes in the reflections from the rod outer segments (ROS) were recorded at a time... (Review)
Review
Intact eyes of frog and mouse were studied by X-ray diffraction. Light-induced changes in the reflections from the rod outer segments (ROS) were recorded at a time resolution of 0.1 and 1 s in frog and mouse, respectively. Lamellar diffraction from disk membranes was observed to the 10th order. In frog, the intensities of seven reflections were found to change significantly on 7-s intense illumination and the lamellar spacing, which was 30.4 nm in darkness, decreased by 0.5%. Time courses of changes in the intensity and the lamellar spacing were similar, saturating at about 7 s. Most of the intensity changes could be attributable to the spacing change. Thus, the effect of light on the electron density distribution was smaller than previously reported. The decrease in the lamellar spacing is attributed to changes in the intracellular ionic concentrations due to the blockage of the dark current. This may be a useful index to study the ionic movements in the cell. Mouse ROS's had a lamellar spacing larger than frog (32.4 nm). The structural changes after illumination were similar to those in frog ROS. This X-ray diffraction technique may be utilized to study functions of photoreceptor cells in transgenic mice and other animals.
Topics: Animals; Anura; Lighting; Mice; Photic Stimulation; Photoreceptor Cells
PubMed: 24095685
DOI: 10.1016/j.exer.2013.09.016 -
Journal of Visualized Experiments : JoVE Nov 2019A method to study desensitization and recovery of crayfish photoreceptors is presented. We performed intracellular electrical recordings of photoreceptor cells in...
A method to study desensitization and recovery of crayfish photoreceptors is presented. We performed intracellular electrical recordings of photoreceptor cells in isolated eyestalks using the discontinuous single electrode-switched voltage-clamp configuration. First, with a razor blade we made an opening in the dorsal cornea to get access to the retina. Thereafter, we inserted a glass electrode through the opening, and penetrated a cell as reported by the recording of a negative potential. Membrane potential was clamped at the photoreceptor's resting potential and a light-pulse was applied to activate currents. Finally, the two light-flash protocol was employed to measure current desensitization and recovery. The first light-flash triggers, after a lag period, the transduction ionic current, which after reaching a peak amplitude decays towards a desensitized state; the second flash, applied at varying time intervals, assesses the state of the light-activated conductance. To characterize the light-elicited current, three parameters were measured: 1) latency (the time elapsed between light flash delivery and the moment in which current achieves 10% of its maximum value); 2) peak current; and 3) desensitization time constant (exponential time constant of the current decay phase). All parameters are affected by the first pulse. To quantify recovery from desensitization, the ratio p2/p1 was employed versus time between pulses. p1 is the peak current evoked by the first light-pulse, and p2 is the peak current evoked by the second pulse. These data were fitted to a sum of exponential functions. Finally, these measurements were carried out as function of circadian time.
Topics: Animals; Astacoidea; Ion Transport; Light; Membrane Potentials; Photoreceptor Cells
PubMed: 31762449
DOI: 10.3791/56258 -
Experimental Eye Research Jul 1989The distribution of the visual pigment protein opsin in postnatal day 8 and adult rat retinal photoreceptor cells was studied using several well characterized monoclonal...
The distribution of the visual pigment protein opsin in postnatal day 8 and adult rat retinal photoreceptor cells was studied using several well characterized monoclonal antibodies against rhodopsin and a sensitive, modified colloidal gold technique. Distribution of opsin was studied in intact tissue, explant cultures and freshly dissociated cell preparation. At PN8 labeling was seen in the plasma membrane overlying the cell body, inner and outer segment. Adult retinas still showed heavy labeling of the cell body and outer segment, but reduced labeling of the inner segment surface. Semi-quantitative estimates of colloidal gold particles bound indicated a ratio of 3-20 times more particles per unit length in the outer vs. the inner segment, depending on tissue age, preparation and antibody. Together with the subcellular localization of other photoreceptor plasma membrane proteins, these data reveal a complex system of membrane domains into which different protein components are segregated.
Topics: Animals; Cell Membrane; Eye Proteins; Microscopy, Electron; Photoreceptor Cells; Rats; Retinal Pigments; Rod Opsins
PubMed: 2527162
DOI: 10.1016/0014-4835(89)90072-9 -
Cellular and Molecular Biology... Jun 1995The DNA and protein synthesis of the bipolar cells and photoreceptor cells of aging mouse retina from fetal to postnatal 1 year were studied by light and electron...
The DNA and protein synthesis of the bipolar cells and photoreceptor cells of aging mouse retina from fetal to postnatal 1 year were studied by light and electron microscopic radioautography. Meanwhile the ultrastructure of these cells was observed by electron microscopy. The bipolar and photoreceptor cells incorporated 3H-thymidine from embryonic day 19 until 1 week after birth, while 3H-leucine from embryonic day 19 to postnatal 1 year. The 3H-thymidine labelled cells had undeveloped cell organelles in their cytoplasm. On the contrary, the unlabelled cells had well developed cell organelles, mainly mitochondria and endoplasmic reticulum in their cytoplasm. The mitochondria became elongated when the outer segments were well developed. The protein synthesis of the bipolar cells and photoreceptor cells as demonstrated with 3H-leucine labeling was vigorous at embryonic day 19 and early postnatal days when the inner and outer segments were formed. The peak of this phenomenon was observed at 1 day after birth. The activity of protein synthesis was also detected at the adult stage. However there was no significant fluctuation in any stages from 14 days after birth to 1 year.
Topics: Aging; Animals; Autoradiography; Cell Differentiation; DNA; Mice; Microscopy, Electron; Photoreceptor Cells; Protein Biosynthesis; Retina
PubMed: 7549795
DOI: No ID Found -
In Vivo (Athens, Greece) 1996Retinal degeneration induced by a single intraperitoneal injection of N-methyl-N-nitrosourea (MNU) in male and female albino (GRS/A and DDD/1) and colored (C57BL) mice...
Retinal degeneration induced by a single intraperitoneal injection of N-methyl-N-nitrosourea (MNU) in male and female albino (GRS/A and DDD/1) and colored (C57BL) mice at 7 weeks of age was examined morphologically 1, 3, 7, 14 and 21 days after the treatment. A dose of 60 mg/kg body weight evoked progressive retinal degeneration in all mice. All albino and colored mice had a comparable progression of photoreceptor cell degeneration by an apoptotic mechanism, as confirmed by morphological and TUNEL methods. Apoptosis had already taken place 1 day after the treatment and was completed by Day 7. This process resulted in a thin remnant of retina with complete loss of photoreceptor cells-21 days after the treatment. During the course of apoptosis, the pigment epithelial cells were maintained in a continuous layer in all strains of mice. In colored mice, several layers of the swollen pigment-enriched cells were seen between the inner nuclear layer and the pigment epithelial layer 14 and 21 days after the treatment. In summary, the destruction of photoreceptor cells by the apoptotic process was the mechanism by which retinal degeneration was induced by MNU.
Topics: Animals; Apoptosis; DNA Fragmentation; Deoxyuracil Nucleotides; Digoxigenin; Female; Injections, Intraperitoneal; Male; Methylnitrosourea; Mice; Mice, Inbred C57BL; Mutagens; Necrosis; Nerve Degeneration; Photoreceptor Cells; Staining and Labeling
PubMed: 8899426
DOI: No ID Found