Melatonin and cortisol profiles in the absence of light perception.
As light plays an important role in the synchronisation of the internal biological clock to the environmental day/night schedule, we compared the 24-h profiles of biological circadian markers in blind and normal sighted individuals. Salivary melatonin and cortisol concentrations were collected every two hours in eleven blind subjects, reporting no conscious light perception, and eleven age- and sex-matched normal sighted controls. Timing of melatonin onset and associated cortisol quiescence period confirm an increased incidence of abnormal circadian patterns in blindness. Additionally, blind subjects showed a greater overall melatonin concentration throughout the 24-h period. Cortisol profiles, including concentration and morning cortisol peaks, on the other hand, did not differ between blind and sighted individuals. These findings support previous reports of an increase in abnormal circadian rhythms and the absence of the entrainment properties of light in blindness.
Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada; Brain Research and Integrative Neuroscience Laboratory, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
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S
Aubin
Brain Research and Integrative Neuroscience Laboratory, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark; Department of Radiology & Biomedical Imaging, Yale University, 300 Cedar Street, New Haven, CT 06520, USA. Electronic address: kupers@sund.ku.dk.
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R
Kupers
Brain Research and Integrative Neuroscience Laboratory, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark; Laboratory of Neuropsychiatry and Psychiatric Centre Copenhagen, University of Copenhagen, Copenhagen, Denmark; Harland Sanders Chair in Visual Science, School of Optometry, University of Montreal, Montreal, Quebec, Canada.
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M
Ptito
Danish Centre for Sleep Medicine, Rigshospitalet, Department of Clinical Neurophysiology, University of Copenhagen, Copenhagen, Denmark.
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Jennum
D000328:Adult; D019540:Area Under Curve; D001766:Blindness / Q000378:metabolism* / Q000503:physiopathology; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008027:Light; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D008875:Middle Aged; D010465:Perception / Q000502:physiology*; D012463:Saliva / Q000378:metabolism*; D018709:Statistics, Nonparametric
D008550:Melatonin; D006854:Hydrocortisone
Blindness; Circadian phase; Cortisol; Melatonin; Sleep