Document Detail


Spectral responses of the human circadian system depend on the irradiance and duration of exposure to light.
MedLine Citation:
PMID:  20463367     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In humans, modulation of circadian rhythms by light is thought to be mediated primarily by melanopsin-containing retinal ganglion cells, not rods or cones. Melanopsin cells are intrinsically blue light-sensitive but also receive input from visual photoreceptors. We therefore tested in humans whether cone photoreceptors contribute to the regulation of circadian and neuroendocrine light responses. Dose-response curves for melatonin suppression and circadian phase resetting were constructed in subjects exposed to blue (460 nm) or green (555 nm) light near the onset of nocturnal melatonin secretion. At the beginning of the intervention, 555-nm light was equally effective as 460-nm light at suppressing melatonin, suggesting a significant contribution from the three-cone visual system (lambda(max) = 555 nm). During the light exposure, however, the spectral sensitivity to 555-nm light decayed exponentially relative to 460-nm light. For phase-resetting responses, the effects of exposure to low-irradiance 555-nm light were too large relative to 460-nm light to be explained solely by the activation of melanopsin. Our findings suggest that cone photoreceptors contribute substantially to nonvisual responses at the beginning of a light exposure and at low irradiances, whereas melanopsin appears to be the primary circadian photopigment in response to long-duration light exposure and at high irradiances. These results suggest that light therapy for sleep disorders and other indications might be optimized by stimulating both photoreceptor systems.
Authors:
Joshua J Gooley; Shantha M W Rajaratnam; George C Brainard; Richard E Kronauer; Charles A Czeisler; Steven W Lockley
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Science translational medicine     Volume:  2     ISSN:  1946-6242     ISO Abbreviation:  Sci Transl Med     Publication Date:  2010 May 
Date Detail:
Created Date:  2010-05-13     Completed Date:  2010-08-20     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101505086     Medline TA:  Sci Transl Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  31ra33     Citation Subset:  IM    
Affiliation:
Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Circadian Rhythm / physiology,  radiation effects*
Dose-Response Relationship, Radiation
Humans
Light
Melatonin / secretion
Photoperiod
Phototherapy
Retina / physiology,  radiation effects
Retinal Cone Photoreceptor Cells / physiology,  radiation effects
Retinal Ganglion Cells / physiology,  radiation effects
Rod Opsins / physiology
Young Adult
Grant Support
ID/Acronym/Agency:
AT002129/AT/NCCAM NIH HHS; M01 RR02635/RR/NCRR NIH HHS; MH45130/MH/NIMH NIH HHS; NS36590/NS/NINDS NIH HHS; T32-HL07901/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Rod Opsins; 0/melanopsin; 73-31-4/Melatonin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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