Photoreceptors

@misc{walls1942the5,
    author = "Walls, G. L",
    title = "The Vertebrate Eye and its Adaptive Radiation",
    year = "1942",
    howpublished = "Bloomfield Hills, Michigan, The Cranbrook Institute of Science",
    note = "talkorigins\_source = {true}; raw\_reference = {Walls, G. L., 1942, The Vertebrate Eye and its Adaptive Radiation: Bloomfield Hills, Michigan, The Cranbrook Institute of Science.}"
}

@article{steven1950some3,
    author = "Steven, D. M",
    title = "Some properties of the photoreceptors of the brook lamprey",
    year = "1950",
    journal = "Journal of Experimental Biology, v. 27, p. 350-364",
    note = "talkorigins\_source = {true}; raw\_reference = {Steven, D. M., 1950, Some properties of the photoreceptors of the brook lamprey: Journal of Experimental Biology, v. 27, p. 350-364.}"
}

@article{steven1963the4,
    author = "Steven, D. M",
    title = "The dermal light sense",
    year = "1963",
    journal = "Biological Reviews, v. 38, p. 204-239",
    note = "talkorigins\_source = {true}; raw\_reference = {Steven, D. M., 1963, The dermal light sense: Biological Reviews, v. 38, p. 204-239.}"
}

@article{denton1970on2,
    author = "Denton, E. J. and Nicol, J. A. C. and Gilpin-Brown, J. B. and Wright, P. G",
    title = {On the "filters" of mesopelagic fish and on a fish emitting red light and especially sensitive to red light},
    year = "1970",
    journal = "Journal of Physiology, v. 208, p. 72P",
    note = {talkorigins\_source = {true}; raw\_reference = {Denton, E. J., Nicol, J. A. C., Gilpin-Brown, J. B., and Wright, P. G., 1970, On the "filters" of mesopelagic fish and on a fish emitting red light and especially sensitive to red light: Journal of Physiology, v. 208, p. 72P.}}
}

@book{ali1984photoreception1,
    author = "Ali, M. A",
    title = "Photoreception and Vision in Invertebrates",
    year = "1984",
    publisher = "New York, Plenum Press",
    note = "talkorigins\_source = {true}; raw\_reference = {Ali, M. A., 1984, Photoreception and Vision in Invertebrates: New York, Plenum Press.}"
}

@article{crossref2003cryptogam,
    title = "Cryptogam blue-light photoreceptors",
    year = "2003",
    journal = "Current Opinion in Plant Biology",
    url = "https://doi.org/10.1016/s1369-5266(02)00006-7",
    doi = "10.1016/s1369-5266(02)00006-7",
    number = "1",
    pages = "91-96",
    volume = "6"
}

This book offers comprehensive coverage of the most important areas in photoreceptors and light signalling. Photoreceptors enable most species to sense not only the presence of light but also the information, such as irradiance, colour or spectral distribution, direction and polarization of light. They are vital, therefore, in providing organisms with energy and information about their surroundings, such as day and night cycles. This book covers the range of photoreceptors that have been discovered to date and the broad range of methods used when researching how they operate, including: action spectroscopy; methods for protein purification; the whole range of molecular biological and genetic methods; and numerous spectroscopic methods, from absorption and fluorescence spectroscopy to X-ray diffraction, used for solving the structure of photoreceptors. Written by leading experts in the field, Photoreceptors and Light Signalling provides the reader with the most recent results and research. This book will be valued by a wide-range of readers, including students of photochemistry, photobiology, biology, chemistry and physics and other professionals in academia.

@misc{crossref2003photoreceptors,
    title = "Photoreceptors and Light Signalling",
    year = "2003",
    abstract = "This book offers comprehensive coverage of the most important areas in photoreceptors and light signalling. Photoreceptors enable most species to sense not only the presence of light but also the information, such as irradiance, colour or spectral distribution, direction and polarization of light. They are vital, therefore, in providing organisms with energy and information about their surroundings, such as day and night cycles. This book covers the range of photoreceptors that have been discovered to date and the broad range of methods used when researching how they operate, including: action spectroscopy; methods for protein purification; the whole range of molecular biological and genetic methods; and numerous spectroscopic methods, from absorption and fluorescence spectroscopy to X-ray diffraction, used for solving the structure of photoreceptors. Written by leading experts in the field, Photoreceptors and Light Signalling provides the reader with the most recent results and research. This book will be valued by a wide-range of readers, including students of photochemistry, photobiology, biology, chemistry and physics and other professionals in academia.",
    url = "https://doi.org/10.1039/9781847551665",
    doi = "10.1039/9781847551665"
}

@incollection{foster2007light,
    author = "Foster, Russell G. and Hankins, Mark W. and Peirson, Stuart N.",
    title = "Light, Photoreceptors, and Circadian Clocks",
    year = "2007",
    booktitle = "Methods in Molecular Biology",
    url = "https://doi.org/10.1007/978-1-59745-257-1\_1",
    doi = "10.1007/978-1-59745-257-1\_1",
    pages = "3-28"
}

@incollection{dowling2016capturing,
    author = "Dowling, John E. and Dowling, Joseph L.",
    title = "Capturing Light—The Photoreceptors",
    year = "2016",
    booktitle = "Vision",
    url = "https://doi.org/10.7551/mitpress/9780262034616.003.0003",
    doi = "10.7551/mitpress/9780262034616.003.0003",
    pages = "45-72"
}

Mutations in GUCY2D gene coding for retinal membrane guanylyl cyclase 1 (RetGC1, or GC-E) can deregulate cGMP synthesis in photoreceptors by guanylyl cyclase activating proteins (GCAPs) via negative Ca2+ feedback and elevate cGMP production in the dark, thus causing autosomal-dominant cone-rod dystrophy (GUCY2D adCORD). We expressed an engineered protein inhibitor of retinal guanylyl cyclase (PIGCY) in transgenic mice of either sex harboring the GUCY2D adCORD RetGC1 mutant Arg838Ser (R838ST g) in order to suppress aberrant production of cGMP in their rods and prevent their fast degeneration. PIGCY did not return the abnormal Ca2+ sensitivity of cGMP synthesis in PIGCYTgR838STg retinas to the normal physiological range, but it reduced the overall rate of cGMP production. Decelerated cGMP production strongly suppressed degeneration of functional rods. By the age of 6 months, 70% of photoreceptor nuclei remained in PIGCYTgR838STg versus 20% in R838STg Retinal response to light detected by electroretinography was preserved in PIGCYTgR838STg mice significantly better than in R838STg. The remaining altered calcium feedback affected the shape of PIGCYTgR838STg rod photoresponses, but overall light sensitivity was not drastically different from normal. Single-photon response amplitude and time-to-peak in PIGCYTgR838STg rods were increased and more variable, but were similar to wild type in fractional light sensitivity and half-saturating light intensity. Consistent with the still abnormal calcium feedback, desensitization under background light in PIGCYTgR838STg rods was increased and their noise was elevated under moderate background illumination as compared to wild type. In summary, PIGCY effectively rescued degenerating GUCY2D adCORD rods while maintaining their functional light sensitivity.Significance statement Elevated cGMP synthesis in photoreceptors caused by mutations deregulating the calcium-sensitive activity of human membrane guanylyl cyclase 1 (RetGC1, GUCY2D) in the dark causes progressing congenital blindness, autosomal dominant cone-rod dystrophy (adCORD). This work is the first to demonstrate that degeneration of transgenic mouse rod photoreceptors harboring a human GUCY2D adCORD RetGC1 mutant can be effectively suppressed in vivo by an engineered protein inhibitor. Reduction of cGMP synthesis rescuing adCORD rods from degeneration moderately affects the shape of light responses but does not disable rod light sensitivity. The findings open the possibility that such an approach could be utilized to treat presently incurable GUCY2D adCORD.

@article{doi101523jneurosci0164262026,
    author = "Sato, Shinya and Peshenko, Igor V and Olshevskaya, Elena V and Kefalov, Vladimir J and Dizhoor, Alexander M",
    title = "Protein Inhibitor of Retinal Membrane Guanylyl Cyclase Rescues Mouse Rod Photoreceptors from GUCY2D Retinal Dystrophy.",
    year = "2026",
    journal = "The Journal of neuroscience: the official journal of the Society for Neuroscience",
    abstract = "Mutations in GUCY2D gene coding for retinal membrane guanylyl cyclase 1 (RetGC1, or GC-E) can deregulate cGMP synthesis in photoreceptors by guanylyl cyclase activating proteins (GCAPs) via negative Ca2+ feedback and elevate cGMP production in the dark, thus causing autosomal-dominant cone-rod dystrophy (GUCY2D adCORD). We expressed an engineered protein inhibitor of retinal guanylyl cyclase (PIGCY) in transgenic mice of either sex harboring the GUCY2D adCORD RetGC1 mutant Arg838Ser (R838ST g) in order to suppress aberrant production of cGMP in their rods and prevent their fast degeneration. PIGCY did not return the abnormal Ca2+ sensitivity of cGMP synthesis in PIGCYTgR838STg retinas to the normal physiological range, but it reduced the overall rate of cGMP production. Decelerated cGMP production strongly suppressed degeneration of functional rods. By the age of 6 months, 70\% of photoreceptor nuclei remained in PIGCYTgR838STg versus 20\% in R838STg Retinal response to light detected by electroretinography was preserved in PIGCYTgR838STg mice significantly better than in R838STg. The remaining altered calcium feedback affected the shape of PIGCYTgR838STg rod photoresponses, but overall light sensitivity was not drastically different from normal. Single-photon response amplitude and time-to-peak in PIGCYTgR838STg rods were increased and more variable, but were similar to wild type in fractional light sensitivity and half-saturating light intensity. Consistent with the still abnormal calcium feedback, desensitization under background light in PIGCYTgR838STg rods was increased and their noise was elevated under moderate background illumination as compared to wild type. In summary, PIGCY effectively rescued degenerating GUCY2D adCORD rods while maintaining their functional light sensitivity.Significance statement Elevated cGMP synthesis in photoreceptors caused by mutations deregulating the calcium-sensitive activity of human membrane guanylyl cyclase 1 (RetGC1, GUCY2D) in the dark causes progressing congenital blindness, autosomal dominant cone-rod dystrophy (adCORD). This work is the first to demonstrate that degeneration of transgenic mouse rod photoreceptors harboring a human GUCY2D adCORD RetGC1 mutant can be effectively suppressed in vivo by an engineered protein inhibitor. Reduction of cGMP synthesis rescuing adCORD rods from degeneration moderately affects the shape of light responses but does not disable rod light sensitivity. The findings open the possibility that such an approach could be utilized to treat presently incurable GUCY2D adCORD.",
    url = "https://pubmed.ncbi.nlm.nih.gov/42045071/",
    doi = "10.1523/JNEUROSCI.0164-26.2026",
    pmid = "42045071"
}

Sleep profiles of the Nile grass rat (Arvicanthis niloticus), a day-active rodent that is widely used in research, have not been fully characterized. Sleep electroencephalograms were therefore recorded in male Nile grass rats maintained under 12/12-hour light-dark (LD) cycles with different light intensities and spectra. A crepuscular elevation in wakefulness was observed under LD cycles of 150-lux white light. Moreover, a stepwise increase in daytime wakefulness and a reduction in daytime non-rapid eye movement sleep were observed at higher light intensities (300 or 1000 lux). The amount of nighttime non-rapid eye movement sleep remained stable regardless of preceding light conditions, whereas delta electroencephalogram power was enhanced during the day and early nighttime under 1000-lux LD cycles, suggesting homeostatic control of sleep quality. Although Nile grass rats have ultraviolet-sensitive photoreceptors, daytime co-exposures of ultraviolet light did not affect daily sleep amounts or quality under 300-lux LD cycles. We then explored correlations between brain activity and sleep-wake levels or light intensities (150 or 1000 lux) using cFos immunostaining in brains sampled at four different times of the day. cFos immunoreactivity in the hypothalamic suprachiasmatic nucleus-the central circadian clock-displayed the highest signal at light onset under 1000-lux LD cycles. Furthermore, cFos immunoreactivity in the anterior paraventricular thalamic nucleus increased at dawn and dusk, and the midday signal was amplified by 1000-lux light. These results elucidate light-dependent sleep-wake profiles in Nile grass rats and suggest the possible involvement of the anterior paraventricular thalamic nucleus in daytime arousal control.Significance Statement Understanding how environmental light shapes sleep-wake regulation in diurnal mammals is essential for developing experimental models relevant to human physiology and sleep disorders. This study provides a comprehensive EEG/EMG-based characterization of sleep architecture in the Nile grass rat, a diurnal rodent with strong potential as a model for seasonal affective disorders. Bright daytime light enhanced arousal, reduced NREM and REM sleep, and increased delta power, revealing intensity-dependent modulation of sleep quantity and quality. cFos mapping further identified the anterior paraventricular thalamus as a candidate node linking light exposure to arousal regulation. These findings position the Nile grass rat as a valuable experimental species for investigating the mechanisms underlying human circadian sleep-wake organization and its modulation by environmental light.

@article{doi101523jneurosci0253262026,
    author = "Tamogami, Sakura and Ikeda, Shoya and Amano, Hiromu and Suzuki, Ryoei and Yamamoto, Riona and Mise, Ryunosuke and Kitade, Suzue and Mochizuki, Takatoshi and Yoshikawa, Tomoko and Morioka, Eri and Ikeda, Masayuki",
    title = "Bright light shapes diurnal sleep-wake rhythms with associated cFos activity in the anterior paraventricular thalamus in the Nile grass rat.",
    year = "2026",
    journal = "The Journal of neuroscience: the official journal of the Society for Neuroscience",
    abstract = "Sleep profiles of the Nile grass rat (Arvicanthis niloticus), a day-active rodent that is widely used in research, have not been fully characterized. Sleep electroencephalograms were therefore recorded in male Nile grass rats maintained under 12/12-hour light-dark (LD) cycles with different light intensities and spectra. A crepuscular elevation in wakefulness was observed under LD cycles of 150-lux white light. Moreover, a stepwise increase in daytime wakefulness and a reduction in daytime non-rapid eye movement sleep were observed at higher light intensities (300 or 1000 lux). The amount of nighttime non-rapid eye movement sleep remained stable regardless of preceding light conditions, whereas delta electroencephalogram power was enhanced during the day and early nighttime under 1000-lux LD cycles, suggesting homeostatic control of sleep quality. Although Nile grass rats have ultraviolet-sensitive photoreceptors, daytime co-exposures of ultraviolet light did not affect daily sleep amounts or quality under 300-lux LD cycles. We then explored correlations between brain activity and sleep-wake levels or light intensities (150 or 1000 lux) using cFos immunostaining in brains sampled at four different times of the day. cFos immunoreactivity in the hypothalamic suprachiasmatic nucleus-the central circadian clock-displayed the highest signal at light onset under 1000-lux LD cycles. Furthermore, cFos immunoreactivity in the anterior paraventricular thalamic nucleus increased at dawn and dusk, and the midday signal was amplified by 1000-lux light. These results elucidate light-dependent sleep-wake profiles in Nile grass rats and suggest the possible involvement of the anterior paraventricular thalamic nucleus in daytime arousal control.Significance Statement Understanding how environmental light shapes sleep-wake regulation in diurnal mammals is essential for developing experimental models relevant to human physiology and sleep disorders. This study provides a comprehensive EEG/EMG-based characterization of sleep architecture in the Nile grass rat, a diurnal rodent with strong potential as a model for seasonal affective disorders. Bright daytime light enhanced arousal, reduced NREM and REM sleep, and increased delta power, revealing intensity-dependent modulation of sleep quantity and quality. cFos mapping further identified the anterior paraventricular thalamus as a candidate node linking light exposure to arousal regulation. These findings position the Nile grass rat as a valuable experimental species for investigating the mechanisms underlying human circadian sleep-wake organization and its modulation by environmental light.",
    url = "https://pubmed.ncbi.nlm.nih.gov/42062070/",
    doi = "10.1523/JNEUROSCI.0253-26.2026",
    pmid = "42062070"
}

Ivermectin (IVM), a widely used anthelmintic and chemotherapeutic agent in both human and veterinary medicine, targets glutamate-gated chloride channels to induce paralysis in nematodes such as Caenorhabditis elegans. Traditionally, IVM-induced paralysis is assessed under brightfield microscopy. Here, we report that exposure to UV or blue wavelengths can induce spontaneous arousal from the IVM-paralyzed state, initiating with twitching and progressing to full swimming motion during light stimulation. This light-induced arousal response is absent in lite-1 null mutants, implicating LITE-1 photoreceptors in mediating this effect..

@article{doi1017912micropubbiology001983,
    author = "Shaw, Magera and Stover, Mylissa and Shults, Crystal and Manjarrez, Jacob R",
    title = "LITE-1 Photoreceptor Mediates Light-Induced Reversal of Ivermectin Paralysis in Caenorhabditis elegans.",
    year = "2026",
    journal = "microPublication biology",
    abstract = "Ivermectin (IVM), a widely used anthelmintic and chemotherapeutic agent in both human and veterinary medicine, targets glutamate-gated chloride channels to induce paralysis in nematodes such as Caenorhabditis elegans. Traditionally, IVM-induced paralysis is assessed under brightfield microscopy. Here, we report that exposure to UV or blue wavelengths can induce spontaneous arousal from the IVM-paralyzed state, initiating with twitching and progressing to full swimming motion during light stimulation. This light-induced arousal response is absent in lite-1 null mutants, implicating LITE-1 photoreceptors in mediating this effect..",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC13110406/",
    doi = "10.17912/micropub.biology.001983",
    pmcid = "PMC13110406",
    pmid = "42046732"
}