Introduction to the Symposium on bistable and sensitizing pigments in vision

Hillman, Peter

doi:10.1007/bf00535441

Cited by 2 publications

(1 citation statement)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The visual pigments coupled to Gq proteins are located in the microvilli of the rhabdomeric PRCs, which are morphologically and biochemically different from the ciliary photoreceptors, rod and cone cells of vertebrates. These photopigments, in general, convert to thermally stable photoproducts with absorption maxima in the visible region of spectrum by light absorption, and exhibit a typical bistable nature . The photoproducts activate the Gq‐type G‐protein, which in turn stimulates phospholipase C, likely a PLCß isoform, resulting in the depolarization of the PRC membrane .…”

Section: Is There a Visual Cycle In The Inner Retina?mentioning

confidence: 99%

Melanopsin and the Non‐visual Photochemistry in the Inner Retina of Vertebrates

Díaz

Morera

Guido

2015

Photochem & Photobiology

View full text Add to dashboard Cite

Melanopsin (Opn4), a member of the G-protein-coupled receptor family, is a vitamin A-based opsin in the vertebrate retina that has been shown to be involved in the synchronization of circadian rhythms, pupillary light reflexes, melatonin suppression and other light-regulated tasks. In nonmammalian vertebrates there are two Opn4 genes, Opn4m and Opn4x, the mammalian and Xenopus orthologs respectively. Opn4x is only expressed in nonmammalian vertebrates including reptiles, fish and birds, while Opn4m is found in a subset of retinal ganglion cells (RGCs), the intrinsically photosensitive (ip) RGCs of the inner retina of both mammals and nonmammalian vertebrates. All opsins described utilize retinaldehyde as chromophore, photoisomerized from 11-cisto all-trans-retinal upon light exposure. Visual retinal photoreceptor cones and rods, responsible for day and night vision respectively, recycle retinoids through a process called the visual cycle that involves the retinal pigment epithelium or glial M€ uller cells. Although Opn4 has been characterized as a bistable photopigment, little is known about the mechanism/s involved in its chromophore regeneration. In this review, we will attempt to shed light on the visual cycle taking place in the inner retina and discuss the state of the art in the nonvisual photochemistry of vertebrates.

show abstract

Section: Is There a Visual Cycle In The Inner Retina?mentioning

confidence: 99%

Melanopsin and the Non‐visual Photochemistry in the Inner Retina of Vertebrates

Díaz

Morera

Guido

2015

Photochem & Photobiology

View full text Add to dashboard Cite

show abstract

Non-visual Opsins and Novel Photo-Detectors in the Vertebrate Inner Retina Mediate Light Responses Within the Blue Spectrum Region

et al. 2020

View full text Add to dashboard Cite

In recent decades, a number of novel non-visual opsin photopigments belonging to the family of G protein-coupled receptors, likely involved in a number of non-image-forming processes, have been identified and characterized in cells of the inner retina of vertebrates. It is now known that the vertebrate retina is composed of visual photoreceptor cones and rods responsible for diurnal/color and nocturnal/black and white vision, and cells like the intrinsically photosensitive retinal ganglion cells (ipRGCs) and photosensitive horizontal cells in the inner retina, both detecting blue light and expressing the photopigment melanopsin (Opn4). Remarkably, these non-visual photopigments can continue to operate even in the absence of vision under retinal degeneration. Moreover, inner retinal neurons and Müller glial cells have been shown to express other photopigments such as the photoisomerase retinal G protein-coupled receptor (RGR), encephalopsin (Opn3), and neuropsin (Opn5), all able to detect blue/violet light and implicated in chromophore recycling, retinal clock synchronization, neuronto-glia communication, and other activities. The discovery of these new photopigments in the inner retina of vertebrates is strong evidence of novel light-regulated activities. This review focuses on the features, localization, photocascade, and putative functions of these novel non-visual opsins in an attempt to shed light on their role in the inner retina of vertebrates and in the physiology of the whole organism.

show abstract

Introduction to the Symposium on bistable and sensitizing pigments in vision

Cited by 2 publications

References 22 publications

Melanopsin and the Non‐visual Photochemistry in the Inner Retina of Vertebrates

Melanopsin and the Non‐visual Photochemistry in the Inner Retina of Vertebrates

Non-visual Opsins and Novel Photo-Detectors in the Vertebrate Inner Retina Mediate Light Responses Within the Blue Spectrum Region

Contact Info

Product

Resources

About