Recovery time (Half-life) from illumination

Range with constant illumination 5min: with flash illumination 17min min
Organism Mouse Mus musculus
Reference Saari JC. Biochemistry of visual pigment regeneration: the Friedenwald lecture. Invest Ophthalmol Vis Sci. 2000 Feb41(2):337-48. p.341 left column top paragraphPubMed ID10670460
Method "Flash illumination of animals and humans has been used with great success in a number of experimental situations. However, it could be argued that physiological conditions are more closely approximated with steady illumination. Thus, [researchers] thought it important to verify that [their] observation of the accumulation of all-trans-retinal during recovery from a flash was not an artifact of the illumination conditions. Dark-adapted mice were subjected to illumination from two 60-W fluorescent bulbs (50 foot-candles). Retinoids were extracted and analyzed at various times after onset of the lights and during the recovery period in the dark. Again, all-trans-retinal was the only retinoid that accumulated in substantial amounts during bleaching and recovery. Figure 7 depicts the amount of all-trans- retinal accumulated during steady state bleaching and during recovery in the dark. The constant light resulted in a steady state with approximately 35% of the visual pigment bleached. When the light was turned off, the all-trans-retinal rapidly decayed to the original dark-adapted value."
Comments "[Researchers] compared the rate of decay of all-trans-retinal produced by steady illumination with that produced by a flash. Approximately the same amount of visual pigment was bleached in each case. The results, shown in Figure 8, illustrate that the recovery from steady illumination is approximately 3.5 times more rapid (halflife [t1/2], 5 minutes with constant illumination. t1/2, 17 minutes with flash illumination). Similar results were reported in a study of phosphorylation of rhodopsin.[Oghuro et al., 1995 PMID 7782279]"
Entered by Uri M
ID 111397