Ultraviolet and blue light induced damage to theDrosophilaretina: Microspectrophotometry and electrophysiology
作者:
StarkWilliam S.,
WalkerKent D.,
EidelJ. Marc,
期刊:
Current Eye Research
(Taylor Available online 1985)
卷期:
Volume 4,
issue 10
页码: 1059-1075
ISSN:0271-3683
年代: 1985
DOI:10.3109/02713688509003351
出版商: Taylor&Francis
数据来源: Taylor
摘要:
Intense ultraviolet (UV) and blue stimulation decreases visual pigment concentration and increases long wavelength fluorescent emission in R1–6 photoreceptors in the white eyed fruit flyDrosophila melanogaster.We used microspectrophotometry to show that the threshold for visual pigment decrease is about 1 log unit lower for UV than for blue light (18.7 vs approximately 19.9 log quanta/cm2respectively). UV and blue stimuli about 0.2 log units brighter had been shown to cause structural degeneration. Above the threshold for structural damage, visual pigment is decreased permanently while below this level, a recovery of visual pigment was achieved within several hours. Microspectrofluorometric data are partially consistent with the hypothesis that the visual pigment is converted into a fluorescent product which had been named M'. M' had been proposed to be a new form of metarhodopsin which absorbs chiefly in the yellow and which has a fluorescent emission in the red; long wavelength stimulation had been reported to regenerate the native visual pigment from M'. Our data suggest that the situation is significantly more complex than this simple model. For instance, we report that long wavelength stimulation regenerates only a small fraction of the visual pigment which had been decreased by UV or blue stimulation. Furthermore, several lines of evidence suggest that other fluorescent products are also created by intense UV and blue stimulation. We were particularly interested in the lower damage threshold for UV light because of the hypothesis that UV visual sensitivity is mediated by a sensitizing pigment which absorbs UV light and transfers its energy to the blue absorbing rhodopsin. Our data suggest that the UV light decreases the rhodopsin without preferentially decreasing the sensitizing pigment.
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