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

DIAZ NM; MORERA LP; GUIDO ME

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016 vol. 92 p. 29 - 29

elanopsin (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 non-mammalian vertebrates there are two Opn4 genes, Opn4m and Opn4x, the mammalian and Xenopus orthologs, respectively. Opn4x is only expressed in non-mammalian 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 non-mammalian vertebrates. All opsins described utilize retinaldehyde as chromophore, photoisomerized from 11-cis- to 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 epitheli