Melanopsin mRNA in the Iris of Red-Eared Slider Turtles (<i>Trachemys scripta elegans</i>)

Cheng, Shuenn‐Ren; Dearworth, James R.; Esckilsen, Scott J.; Kubera, Cathryn L.; Anderson, Christopher W.; Goldberg, Laura A.; Selvarajah, Brian P.; D'souza, Melroy S.; Hartnett, Lauren P.; Chejlava, Michael J.; Sherma, Joseph; Perlow, David R.; Ho, Eric S.

doi:10.1670/16-046

Cited by 4 publications

(3 citation statements)

References 70 publications

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“…One of these novel opsins, melanopsin, which underlies many nonimage-forming visual responses, including part of the retinally-mediated pupil response (Section 5.1), has an absorption spectrum very similar to that of rod visual pigments, with maximum sensitivity around 480nm (Lucas et al, 2001;Bailes & Lucas, 2010). It has also been localised in the iris of amphibia (Provencio et al, 1998), turtles (Cheng et al, 2017), and mice (Xue et al, 2011;Vugler et al, 2015).…”

Section: Intrinsic Iris Photosensitivitymentioning

confidence: 99%

The pupillary light responses of animals; a review of their distribution, dynamics, mechanisms and functions

Douglas

2018

Progress in Retinal and Eye Research

103

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The timecourse and extent of changes in pupil area in response to light are reviewed in all classes of vertebrate and cephalopods. Although the speed and extent of these responses vary, most species, except the majority of teleost fish, show extensive changes in pupil area related to light exposure. The neuromuscular pathways underlying light-evoked pupil constriction are described and found to be relatively conserved, although the precise autonomic mechanisms differ somewhat between species. In mammals, illumination of only one eye is known to cause constriction in the unilluminated pupil. Such consensual responses occur widely in other animals too, and their function and relation to decussation of the visual pathway is considered. Intrinsic photosensitivity of the iris muscles has long been known in amphibia, but is in fact widespread in other animals. The functions of changes in pupil area are considered. In the majority of species, changes in pupil area serve to balance the conflicting demands of high spatial acuity and increased sensitivity in different light levels. In the few teleosts in which pupil movements occur they do not serve a visual function but play a role in camouflaging the eye of bottom-dwelling species. The occurrence and functions of the light-independent changes in pupil size displayed by many animals are also considered. Finally, the significance of the variations in pupil shape, ranging from circular to various orientations of slits, ovals, and other shapes, is discussed.

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Section: Intrinsic Iris Photosensitivitymentioning

confidence: 99%

The pupillary light responses of animals; a review of their distribution, dynamics, mechanisms and functions

Douglas

2018

Progress in Retinal and Eye Research

103

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“…Thus, we isolated the iris in the presence of atropine (1 mM), an antagonist of muscarinic ACh receptors, to block Reduction rates were in general larger than those observed in intact eyes, most likely because the iris sphincter muscle must overcome less resistance and can thus achieve a larger contraction. The iris-intrinsic PLR is mediated by melanopsin in other vertebrates 4,6,24 , which has been shown to be expressed in the fibers of the iris sphincter muscle. 5 Although melanopsin expression was previously reported in the lamprey retina 25 , its presence in the iris was unknown.…”

Section: The Isolated Iris Shows Plr Mediated By Melanopsinmentioning

confidence: 99%

“…Then, the EWN sends signals to the ciliary ganglion through the oculomotor nerve (nIII), and efferent fibers from the ciliary ganglion enter the ocular globe, travelling to the iris sphincter muscle and releasing acetylcholine (Ach) 1 . Additionally, fish, amphibians, birds, and nocturnal/crepuscular mammals exhibit a PLR mechanism that is intrinsic to the iris, mediated by sphincter muscle cells that express melanopsin and can thus act as photoreceptors and evoke muscle contracion [3][4][5][6] . These melanopsin-expressing muscle fibers are in turn connected to adjacent muscle fibers via gap-junctions, allowing the spread of the excitability changes evoked by light 5 .…”

Section: Introductionmentioning

confidence: 99%

Direct retino-iridal projections and intrinsic iris contraction mediate the pupillary light reflex in early vertebrates

Jiménez-López,

Rivas-Ramírez,

Barandela

et al. 2024

Preprint

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The pupillary light reflex (PLR) adapts the amount of light reaching the retina, protecting it and improving image formation. Two PLR mechanisms have been described in vertebrates. First, the pretectum receives retinal inputs and projects to the Edinger-Westphal nucleus (EWN), which targets the ciliary ganglion through the oculomotor nerve (nIII). Postganglionic fibers enter the eye-globe, travelling to the iris sphincter muscle. Additionally, some vertebrates exhibit an iris-intrinsic PLR mechanism mediated by sphincter muscle cells that express melanopsin inducing muscle contraction. Given the high degree of conservation of the lamprey visual system, we investigated the mechanisms underlying the PLR to shed light onto their evolutionary origins. Recently, a PLR mediated by melanopsin was demonstrated in lampreys, suggested to be brain mediated. Remarkably, we found that PLR is instead mediated by direct retino-iridal cholinergic projections, a mechanism not demonstrated before, although suggested to be present in mice. This retina-mediated PLR acts synergistically with the iris-intrinsic mechanism mediated by melanopsin, which has contribution of gap junctions, as in other vertebrates. In contrast, we show that lampreys lack the brain-mediated PLR. Our results suggest that two eye-intrinsic PLR mechanisms were present in early vertebrate evolution, whereas the brain-mediated PLR has a more recent origin.

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Quantum Mechanics/Molecular mechanics calculations predict A1, not A2, is present in melanopsin (Opn4m) of red-eared slider turtles (Trachemys scripta elegans)

et al. 2023

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Melanopsin mRNA in the Iris of Red-Eared Slider Turtles (Trachemys scripta elegans)

Cited by 4 publications

References 70 publications

The pupillary light responses of animals; a review of their distribution, dynamics, mechanisms and functions

The pupillary light responses of animals; a review of their distribution, dynamics, mechanisms and functions

Direct retino-iridal projections and intrinsic iris contraction mediate the pupillary light reflex in early vertebrates

Quantum Mechanics/Molecular mechanics calculations predict A1, not A2, is present in melanopsin (Opn4m) of red-eared slider turtles (Trachemys scripta elegans)

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