Purchase this article with an account.
JC Saari, GG Garwin, M Nawrot; Visual Cycle Activity in Mice Exposed to Constant Illumination . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1403.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Following a flash, all-trans-retinal and all-trans-retinyl ester accumulate transiently in mouse retina during regeneration of the visual pigment. We examined the retinoid profile in mice adapted to constant illumination to determine if the same retinoids accumulated. Methods: Albino mice were dark-adapted and exposed to constant illumination that bleached ca. 40% of their visual pigments, followed by a recovery period in the dark. Eyes were removed at various times and visual cycle retinoids were extracted and analyzed by HPLC. Rhodopsin concentrations were determined by differential spectrophotometry. Results: During the period of constant illumination (60 or 90 min), all-trans-retinal increased immediately (15 min) and gradually decreased in amount. Retinyl esters gradually increased and became the major all-trans-retinoid after 30 min, a finding not noted in a previous study (Saari, 2000). All-trans- and 11-cis-retinol changed little during the period of constant illumination and recovery in the dark. The ratio of all-trans- to 11-cis-retinyl ester (ca. 95 to 5) did not change during the period of constant illumination. Conclusion: The accumulation of all-trans-retinal and all-trans-retinyl esters, during constant illumination, is similar to that reported for flash illumination (Saari et al., 2001). The gradual, apparent conversion of all-trans-retinal to all-trans-retinyl esters suggests that reduction is more rapid than isomerization. The unvarying predominance of all-trans-retinyl esters during constant illumination indicates that the rate of utilization of 11-cis-retinoids is more rapid than their generation.
This PDF is available to Subscribers Only