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  • 1
    Publication Date: 1999-04-16
    Description: In mammals, ocular photoreceptors mediate an acute inhibition of pineal melatonin by light. The effect of rod and cone loss on this response was assessed by combining the rd mutation with a transgenic ablation of cones (cl) to produce mice lacking both photoreceptor classes. Despite the loss of all known retinal photoreceptors, rd/rd cl mice showed normal suppression of pineal melatonin in response to monochromatic light of wavelength 509 nanometers. These data indicate that mammals have additional ocular photoreceptors that they use in the regulation of temporal physiology.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lucas, R J -- Freedman, M S -- Munoz, M -- Garcia-Fernandez, J M -- Foster, R G -- New York, N.Y. -- Science. 1999 Apr 16;284(5413):505-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Sir Alexander Fleming Building, Imperial College of Science, Technology and Medicine, London, SW7 2AZ, UK. r.j.lucas@ic.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10205062" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biological Clocks/physiology ; Circadian Rhythm/*physiology ; Cryptochromes ; Darkness ; *Drosophila Proteins ; *Eye Proteins ; Flavoproteins/genetics/physiology ; *Light ; Light Signal Transduction ; Melatonin/*metabolism ; Mice ; Mice, Inbred C3H ; Mice, Transgenic ; *Photoreceptor Cells, Invertebrate ; Photoreceptor Cells, Vertebrate/*physiology ; Pineal Gland/*metabolism ; Receptors, G-Protein-Coupled ; Retina/cytology/*physiology ; Retinal Ganglion Cells/physiology ; Retinal Pigments/genetics/physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 2
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-02-23
    Description: The pacemaker role of the suprachiasmatic nucleus in a mammalian circadian system was tested by neural transplantation by using a mutant strain of hamster that shows a short circadian period. Small neural grafts from the suprachiasmatic region restored circadian rhythms to arrhythmic animals whose own nucleus had been ablated. The restored rhythms always exhibited the period of the donor genotype regardless of the direction of the transplant or genotype of the host. The basic period of the overt circadian rhythm therefore is determined by cells of the suprachiasmatic region.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ralph, M R -- Foster, R G -- Davis, F C -- Menaker, M -- HD13162/HD/NICHD NIH HHS/ -- HD18686/HD/NICHD NIH HHS/ -- MH09483/MH/NIMH NIH HHS/ -- New York, N.Y. -- Science. 1990 Feb 23;247(4945):975-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, University of Virginia, Charlottesville 22903.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2305266" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Circadian Rhythm/genetics/*physiology ; Cricetinae ; Immunohistochemistry ; Male ; Mutation ; Nerve Tissue/*transplantation ; Neuropeptide Y/analysis ; Suprachiasmatic Nucleus/embryology/*physiology ; Vasopressins/analysis
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2003-01-11
    Description: In the mammalian retina, a small subset of retinal ganglion cells (RGCs) are intrinsically photosensitive, express the opsin-like protein melanopsin, and project to brain nuclei involved in non-image-forming visual functions such as pupillary light reflex and circadian photoentrainment. We report that in mice with the melanopsin gene ablated, RGCs retrograde-labeled from the suprachiasmatic nuclei were no longer intrinsically photosensitive, although their number, morphology, and projections were unchanged. These animals showed a pupillary light reflex indistinguishable from that of the wild type at low irradiances, but at high irradiances the reflex was incomplete, a pattern that suggests that the melanopsin-associated system and the classical rod/cone system are complementary in function.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lucas, R J -- Hattar, S -- Takao, M -- Berson, D M -- Foster, R G -- Yau, K-W -- R01 EY006837/EY/NEI NIH HHS/ -- R01 EY006837-16A1/EY/NEI NIH HHS/ -- R01 EY014596/EY/NEI NIH HHS/ -- R01 EY014596-01/EY/NEI NIH HHS/ -- R37 EY006837/EY/NEI NIH HHS/ -- R37 EY006837-13/EY/NEI NIH HHS/ -- R37 EY006837-14/EY/NEI NIH HHS/ -- R37 EY006837-15/EY/NEI NIH HHS/ -- R37 EY006837-15S1/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 2003 Jan 10;299(5604):245-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Integrative and Molecular Neuroscience, Division of Neuroscience and Psychological Medicine, Faculty of Medicine, Imperial College London, Charing Cross Campus, St. Dunstans Road, London W6 8RF, UK. r.j.lucas@ic.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12522249" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptation, Ocular ; Animals ; Carbachol/pharmacology ; Circadian Rhythm ; Darkness ; *Light ; Light Signal Transduction ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Olivary Nucleus/cytology/physiology ; Phenotype ; Photoreceptor Cells, Vertebrate/physiology ; Pupil/drug effects/*physiology ; *Reflex, Pupillary ; Retinal Degeneration/genetics/physiopathology ; Retinal Ganglion Cells/*physiology ; Rod Opsins/*genetics/*physiology ; Suprachiasmatic Nucleus/physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 194 (1962), S. 91-92 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] It is now reported that lathyrine absorbs two molecules of hydrogen when reduced under these conditions, and that the reduced compound has been isolated as a monohydrate m.p. above 250 (decomp.) [〈x]2! + 64-11 in water (c., 1-1). Found: C, 40-87; H, 7-91. C7H14O2N4.H2O requires C, 41-18; H, 7-84 ...
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  • 5
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In the mammalian retina, besides the conventional rod–cone system, a melanopsin-associated photoreceptive system exists that conveys photic information for accessory visual functions such as pupillary light reflex and circadian photo-entrainment. On ablation of the melanopsin gene, ...
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 165 (1989), S. 553-563 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunocytochemistry with a rod-specific antiserum was used to study the post-hatch development (2 days–300 days) of photoreceptor elements within the pineal of the Japanese quail. At all ages staining was restricted to limited numbers of pinealocytes scattered throughout the gland. An enzyme-linked immunosorbent assay (ELISA), with the same rod-specific antibody, was then used to obtain a quantitative measure of rod opsin in total eye and pineal extracts in both the developing retina and pineal. The opsin content of both tissues shows a marked increase during the first 30 days after hatch and then plateaued to 0.84±0.02 nmoles opsin in the eye and 2.20±0.11 pmoles opsin equivalents in the pineal. The increase in opsin in the retina may be associated with continued post-hatch development of the photoreceptors. We then attempted to demonstrate the presence of the rhodopsin chromophore within pineal and retinal extracts using HPLC analysis. In both retinal and pineal extracts, 11-cis retinaldehyde was identified and a light-induced shift from the 11-cis to the all-trans isomer was clearly shown. This analysis also allowed us to calculate the total content of 11-cis and all-trans retinaldehyde (derived from both rod and non-rod photoreceptors) of the eye and pineal (eye: 1.7±0.2 nmoles; pineal: 4.6±0.5 pmoles). In the quail eye, the total amount of retinaldehyde is more than twice the amount of rod-like opsin. This probably reflects the large contribution of cones in the quail retina; the cone pigments will contribute to the retinaldehyde content but are not recognized by the rodspecific antibodies. In the pineal, we also found more than double the concentration of retinaldehyde than we would have predicted from the amount of rod-like opsin. These results, coupled with our immunocytochemical findings, suggest that the quail pineal contains at least two classes of photoreceptor, some ‘rod-like’, others ‘non rod-like’.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 165 (1989), S. 565-572 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A rod-specific antiserum was used to immunolabel elements within the retina and pineal of the adult Djungarian hamster and Welsh Mountain sheep. In the retina immunostaining was localized to the outer segments and perikarya of photoreceptor cells, while in the pineal limited numbers of labelled pinealocytes were scattered throughout the gland. An enzyme-linked immunosorbent assay (ELISA) was then used to obtain a quantitative measure of rod opsin in total eye and pineal extracts from the Djungarian hamster. Total rod opsin (±SEM) in the eye was measured by absorbance spectroscopy (1.88±0.10 nmoles opsin/eye) and by using the ELISA (1.75±0.02 nmoles opsin/eye). The opsin content from a total of 56 pineals gave a mean value of 0.34±0.01 pmoles opsin/pineal. Since a functional photopigment should be coupled in a 1∶1 ratio to a chromophore, we investigated whether we could identify 11 -cis and/or alltrans retinaldehydes in the pineal extracts by quantitative extraction and HPLC analysis as the oximes. No evidence of 11-cis or all-trans retinaloxime could be found, the chromatograms were indistinguishable from those produced by extracts of cortical brain tissue. We conclude that the opsin present within the adult hamster pineal is not coupled to the common vertebrate retinaldehyde chromophore, and as a result, is unlikely to be part of a functional photopigment.
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  • 8
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study was undertaken to examine the effect of electrical stimulation of the hypothalamus at different times of day on luteinizing hormone (LH) secretion in male castrated quail on short days (8L∶16D). The posterior hypothalamus was stimulated with square-wave pulses of 80 μA for 2 min through chronically-implanted platinum microelectrodes. Stimulation was carried out on each quail at 4 (treatment A), 10 (B), or 14 h (C) after dawn. Plasma LH levels were increased markedly within 2 min of ending the stimulation but reached basal levels again over the next 20 min or so. The absolute increase was significantly greater in treatment B (10 h after lights on) than at the other times tested. This is consistent with a rhythm in hypothalamic responsivity. The results are discussed in the context of the rhythm of photoinducibility which occurs early in the night and which is used by quail as a photoperiodic clock to regulate seasonal reproduction.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 169 (1991), S. 39-50 
    ISSN: 1432-1351
    Keywords: Photoreception ; Retinally degenerate ; Mouse ; Circadian ; Rods ; Cones ; 11-cis retinaldehyde ; Immunocytochemistry ; HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We have examined the effects of light on circadian locomotor rhythms in retinally degenerate mice (C57BL/6J mice homozygous for the rd allele: rd/rd). The sensitivity of circadian photoreception in these mice was determined by varying the irradiance of a 15 min light pulse (515 nm) given at circadian time 16 and meauring the magnitude of the phase shift of the locomotor rhythm. Experiments were performed on animals 80 days of age. Despite the loss of visual photoreceptors in the rd/rd retina, animals showed circadian responses to light that were indistinguishable from mice with normal retinas (rd/+ and +/+). While no photoreceptor outersegments were identified in the retina of rd/rd animals (80–100 days of age), we did identify a small number of perikarya that were immunoreactive for cone opsins, and even fewer cells that contained rod opsin. Using HPLC, we demonstrated the presence and photoisomerization of the rhodopsin chromophore 11-cis retinaldehyde. The rd/rd retinas contained about 2% of 11-cis retinaldehyde found in +/+ retinas. We have yet to determine whether the opsin immunoreactive perikarya or some other unidentified cell type mediate circadian light detection in the rd/rd retina.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 157 (1985), S. 519-528 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A technique has been developed for the investigation of the photopigment involved in the photoperiodic control of reproduction in Japanese quail,Coturnix coturnix. When these photoreceptors were exposed to white or monochromatic light a clear relationship was found between light intensity and the extent of photo-induced luteinizing hormone (LH) secretion. A spectroradiometric investigation of the passage of light through the skull and brain enabled us to illuminate the hypothalamic region with equal numbers of photons at a range of wavelengths. Action spectra were then conducted and showed a photopigment with a peak sensitivity at wavelengths near 500 nm. An excellent match was obtained when the standard absorption spectrum for a rhodopsin was fitted to the action spectrum, suggesting a rhodopsin maximally sensitive at 492 nm. The absolute sensitivity of the photoreceptors was calculated at a range of wavelengths: with light at 500 nm, 2.85×10−12 μE·cm−2·s−1 triggered the photoperiodic response. This level of sensitivity is matched only by the rhodopsin visual pigments.
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