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Author Kozaki, T.; Hidaka, Y.; Takakura, J.-Y.; Kusano, Y. url  doi
openurl 
  Title Salivary melatonin suppression under 100-Hz flickering blue light and non-flickering blue light conditions Type Journal Article
  Year 2020 Publication Neuroscience Letters Abbreviated Journal Neurosci Lett  
  Volume 722 Issue Pages (down) 134857  
  Keywords Human Health; Flickering light; Intrinsically photosensitive retinal ganglion cell; Light; Light emitting diode; Melatonin  
  Abstract Bright light at night has been known to suppress melatonin secretion. Photoreceptors, known as intrinsically photosensitive retinal ganglion cells (ipRGCs), project dark/bright information into the superchiasmatic nucleus, which regulates the circadian system. Electroretinograms of ipRGCs show fluctuation that is synchronized with light ON-OFF stimulation. This finding suggests that the flickering condition of light may have an impact on our circadian system. In this study, we evaluate light-induced melatonin suppression under flickering and non-flickering light conditions. Fifteen male subjects between the ages of 20 and 23 years (mean +/- SD, 21.9 +/- 1.9) were exposed to three light conditions (dim, 100-Hz flickering and non-flickering light) from 1:00 a.m. to 2:30 a.m. Saliva samples were taken just before 1:00 and at 1:15, 1:30, 2:00, and 2:30 a.m. Repeated-measure t-test with Bonferroni correction showed a significant decrease in melatonin levels under both 100-Hz and non-flickering light conditions compared to dim light conditions after 2:00 a.m. Moreover, at 2:30 a.m., the rate of change in melatonin level under 100 Hz of flickering light was significantly lower than that under non-flickering light. Our present findings suggest that 100-Hz flickering light may suppress melatonin secretion more than non-flickering light.  
  Address Department of Health and Nutrition Sciences, Nishikyushu University, 4490-9 Osaki, Kanzaki, Japan  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3940 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:32097701 Approved no  
  Call Number GFZ @ kyba @ Serial 2855  
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Author Moaraf, S.; Vistoropsky, Y.; Pozner, T.; Heiblum, R.; Okuliarova, M.; Zeman, M.; Barnea, A. url  doi
openurl 
  Title Artificial light at night affects brain plasticity and melatonin in birds Type Journal Article
  Year 2019 Publication Neuroscience Letters Abbreviated Journal Neurosci Lett  
  Volume in press Issue Pages (down) 134639  
  Keywords Animals; Artificial Light At Night (ALAN); cell proliferation; circadian cycle; melatonin; neuronal densities; zebra finches (Taeniopygia guttata)  
  Abstract Artificial light at night (ALAN), which disrupts the daily cycle of light, has vast biological impacts on all organisms, and is also associated with several health problems. The few existing studies on neuronal plasticity and cognitive functions in mammals indicate that a disruption of the circadian cycle impairs learning and memory and suppresses neurogenesis. However, nothing is known about the effect of ALAN on neuronal plasticity in birds. To this end, zebra finches (Taeniopygia guttata) were exposed to ecologically relevant ALAN intensities (0.5, 1.5 and 5 lux), treated with BrdU to quantify cell proliferation in their ventricular zone (VZ), and compared to controls that were kept under dark nights. We found, in our diurnal birds, that ALAN significantly increased cell proliferation in the VZ. However, neuronal densities in two brain regions decreased under ALAN, suggesting neuronal death. In addition, ALAN suppressed nocturnal melatonin production in a dose-dependent manner, and might also increase body mass. Taken together, our findings add to the notion of the deleterious effect of ALAN.  
  Address Department of Natural and Life Sciences, The Open University of Israel, Ra'anana, 43107, Israel  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3940 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:31760086 Approved no  
  Call Number GFZ @ kyba @ Serial 2760  
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