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All-trans Retinal Mediates Light-Induced Oxidation in Single Living Rod Photoreceptors

Kosuke Masutomi, Chunhe Chen, Kei Nakatani, Yiannis Koutalos

Photochem Photobiol. Nov-Dec 2012;88(6):1356-61.

PMID: 22417174

Abstract:

All-trans retinal is a potent photosensitizer that is released in photoreceptor outer segments by the photoactivated visual pigment following the detection of light. Photoreceptor outer segments also contain high concentrations of polyunsaturated fatty acids, and are thus particularly susceptible to oxidative damage such as that initiated by light via a photosensitizer. Upon its release, all-trans retinal is reduced within the outer segment to all-trans retinol, through a reaction requiring metabolic input in the form of NADPH. The phototoxic potential of physiologically generated all-trans retinal was examined in single living rod photoreceptors obtained from frog (Rana pipiens) retinas. Light-induced oxidation was measured with fluorescence imaging using an oxidation-sensitive indicator dye from the shift in fluorescence between the intact and oxidized forms. Light-induced oxidation was highest in metabolically compromised rod outer segments following photoactivation of the visual pigment rhodopsin, and after a time interval, sufficiently long to ensure the release of all-trans retinal. Furthermore, light-induced oxidation increased with the concentration of exogenously added all-trans retinal. The results show that the all-trans retinal generated during the detection of light can mediate light-induced oxidation. Its removal through reduction to all-trans retinol protects photoreceptor outer segments against light-induced oxidative damage.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP116314 all trans-Retinal all trans-Retinal 116-31-4 Price
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