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NUITFRANCE - Bibliothèque - Fiche bibliographique
Bibliothèque
Cette rubrique recense :
- de la documentation sur les différents thèmes de la nuit (vie nocturne, pollution lumineuse, pollution sonore, ...).
- les données informatiques relatives à l'éclairage public digitalisées et mises à dispositions en open data par certaines communes,
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► Fiche bibliographique
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Document " Circadian effects of light no brighter than moonlight "
Type de document : |
Articles de revue scientifique |
Thème du document : |
Nuit menacée - Lumière artificielle - Impacts sur les rythmes biologiques |
Groupe biologique : |
Mammifères hors humains et chauves-souris |
Auteur(s) : |
EVANS J.A.
ELLIOTT J.A.
GORMAN M.R.
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Date de publication : |
Août 2007 |
Langue : |
English/Anglais |
Nom du périodique : |
Journal of Biological Rhythms |
Précisions : |
Volume 22. Numéro 4. Pages 356-67 |
Lien contenu/source : |
http://jbr.sagepub.com/content/22/4/356.long |
DOI : |
10.1177/0748730407301988 |
Mots-clefs : |
Circadian visual system
Constant conditions
Dim light
Irradiance
Phase response curve
Phase shift
PRC
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Citation courte : |
Evans et al. (2007) |
Citation complète (format NuitFrance) : |
EVANS J.A., ELLIOTT J.A. & GORMAN M.R. (2007). Circadian effects of light no brighter than moonlight. Journal of Biological Rhythms. Volume 22. Numéro 4. Pages 356-67. |
Résumé du document : |
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In mammals, light entrains endogenous circadian pacemakers by inducing daily phase shifts via a photoreceptor mechanism recently discovered in retinal ganglion cells. Light that is comparable in intensity to moonlight is generally ineffective at inducing phase shifts or suppressing melatonin secretion, which has prompted the view that circadian photic sensitivity has been titrated so that the central pacemaker is unaffected by natural nighttime illumination. However, the authors have shown in several different entrainment paradigms that completely dark nights are not functionally equivalent to dimly lit nights, even when nighttime illumination is below putative thresholds for the circadian visual system. The present studies extend these findings. Dim illumination is shown here to be neither a strong zeitgeber, consistent with published fluence response curves, nor a potentiator of other zeitgebers. Nevertheless, dim light markedly alters the behavior of the free-running circadian pacemaker. Syrian hamsters were released from entrained conditions into constant darkness or dim narrowband green illumination (~0.01 lx, 1.3 x 10(-9) W/cm(2), peak lambda = 560 nm). Relative to complete darkness, constant dim light lengthened the period by ~0.3 h and altered the waveform of circadian rhythmicity. Among animals transferred from long day lengths (14 L:10 D) into constant conditions, dim illumination increased the duration of the active phase (alpha) by ~3 h relative to complete darkness. Short day entrainment (8 L:16 D) produced initially long alpha that increased further under constant dim light but decreased under complete darkness. In contrast, dim light pulses 2 h or longer produced effects on circadian phase and melatonin secretion that were small in magnitude. Furthermore, the amplitude of phase resetting to bright light and nonphotic stimuli was similar against dimly lit and dark backgrounds, indicating that the former does not directly amplify circadian inputs. Dim illumination markedly alters circadian waveform through effects on alpha, suggesting that dim light influences the coupling between oscillators theorized to program the beginning and end of subjective night. Physiological mechanisms responsible for conveying dim light stimuli to the pacemaker and implications for chronotherapeutics warrant further study.
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Saisie sur NuitFrance par : |
Rosor |
Saisie sur NuitFrance en : |
Septembre 2014 |
Identifiant NuitFrance : |
NF-BIBLI-503 |
Permalien de la fiche NuitFrance : |
http://www.nuitfrance.fr/?page=donneesdoc&partie=fiche-bibliographique&id_doc=503 |
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