title: Molecular circadian rhythm shift due to bright light exposure before bedtime is related to subthreshold bipolarity.
abstract: This study examined the link between circadian rhythm changes due to bright light exposure and subthreshold bipolarity. Molecular circadian rhythms, polysomnography, and actigraphy data were studied in 25 young, healthy male subjects, divided into high and low mood disorder questionnaire (MDQ) score groups. During the first 2 days of the study, the subjects were exposed to daily-living light (150 lux) for 4 hours before bedtime. Saliva and buccal cells were collected 5 times a day for 2 consecutive days. During the subsequent 5 days, the subjects were exposed to bright light (1,000 lux), and saliva and buccal cell samples were collected in the same way. Molecular circadian rhythms were analyzed using sine regression. Circadian rhythms of cortisol (F = 16.956, p < 0.001) and relative PER1/ARNTL gene expression (F = 122.1, p < 0.001) showed a delayed acrophase in both groups after bright light exposure. The high MDQ score group showed a significant delay in acrophase compared to the low MDQ score group only in salivary cortisol (F = 8.528, p = 0.008). The high MDQ score group showed hypersensitivity in cortisol rhythm shift after bright light exposure, suggesting characteristic molecular circadian rhythm changes in the high MDQ score group may be related to biological processes downstream from core circadian clock gene expression.
authors.affiliation: Department of Psychiatry, Korea University College of Medicine, Seoul, South Korea.|Sleep-Wake Disorders Center, Korea University Anam Hospital, Seoul, South Korea.
authors.forename: Chul-Hyun
authors.initials: CH
authors.lastname: Cho
authors.affiliation: Department of Biomedical Science, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Joung-Ho
authors.initials: JH
authors.lastname: Moon
authors.affiliation: Department of Psychiatry, Korea University College of Medicine, Seoul, South Korea.|Sleep-Wake Disorders Center, Korea University Anam Hospital, Seoul, South Korea.
authors.forename: Ho-Kyoung
authors.initials: HK
authors.lastname: Yoon
authors.affiliation: Department of Psychiatry, Gachon University School of Medicine, Incheon, South Korea.
authors.forename: Seung-Gul
authors.initials: SG
authors.lastname: Kang
authors.affiliation: Department of Biomedical Science, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Dongho
authors.initials: D
authors.lastname: Geum
authors.affiliation: Department of Legal Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Gi-Hoon
authors.initials: GH
authors.lastname: Son
authors.affiliation: Department of Lighting Environment Research, Korea Institute of Lighting Technology, Seoul, South Korea.
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Lim
authors.affiliation: Department of Psychiatry, Korea University College of Medicine, Seoul, South Korea.|Sleep-Wake Disorders Center, Korea University Anam Hospital, Seoul, South Korea.
authors.forename: Leen
authors.initials: L
authors.lastname: Kim
authors.affiliation: Department of Preventive Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Eun-Il
authors.initials: EI
authors.lastname: Lee
authors.affiliation: Department of Psychiatry, Korea University College of Medicine, Seoul, South Korea.|Sleep-Wake Disorders Center, Korea University Anam Hospital, Seoul, South Korea.|Department of Biomedical Science, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Heon-Jeong
authors.initials: HJ
authors.lastname: Lee
mesh_terms: D056930:ARNTL Transcription Factors / Q000378:metabolism*; D056044:Actigraphy; D000328:Adult; D002940:Circadian Rhythm / Q000528:radiation effects*; D005786:Gene Expression Regulation / Q000528:radiation effects; D064368:Healthy Volunteers; D006801:Humans; D008027:Light; D008297:Male; D009061:Mouth Mucosa / Q000378:metabolism*; D056950:Period Circadian Proteins / Q000378:metabolism*; D017286:Polysomnography; D012463:Saliva / Q000378:metabolism*; D012890:Sleep / Q000528:radiation effects; D055815:Young Adult
chemical_list: D056930:ARNTL Transcription Factors; C538960:BMAL1 protein, human; C539022:PER1 protein, human; D056950:Period Circadian Proteins