University of Oulu

FLYKTMAN, A., JERNFORS, T., MANTTARI, S., NISSILA, J., TIMONEN, M., SAARELA, S.. Transcranial Light Alters Melanopsin and Monoamine Production in Mouse (Mus musculus) Brain. Journal of Neurology Research, North America, 7, may. 2017.

Transcranial light alters melanopsin and monoamine production in mouse (Mus musculus) brain

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Author: Flyktman, Antti1,2; Jernfors, Toni1; Manttari, Satu3;
Organizations: 1Department of Ecology and Genetics, University of Oulu, PO Box 3000, FIN-90014, Oulu, Finland
2Center for Life Course Health Research, University of Oulu, PO Box 5000, FIN-90014, Oulu, Finland
3Finnish Institute of Occupational Health, Aapistie 1, FIN-90220 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.7 MB)
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Language: English
Published: Elmer Press, 2017
Publish Date: 2019-06-19


Background: The mammalian circadian system sets a rhythm for the appropriate occurrence of physiological and behavioral phenomena during a 24-h period. Since the duration of the circadian system is usually less or more than 24 h, it must be entrained regularly and light is the governing stimulus of the rhythm. The target for light stimulus is the master circadian clock, which is located in the suprachiasmatic nucleus in the hypothalamus. One of the key molecules transmitting light information and entraining the clock is melanopsin (OPN4), a G protein-coupled molecule that is found most abundantly in the retina and brain. Although light stimulus is usually mediated through the eyes, light has an ability to penetrate the skull. Here, we present the effect of transcranial light illumination on OPN4 and serotonin expression in the mouse brain.

Methods: Male mice were randomly assigned to a control group, morning-light group and evening-light group, and animals were illuminated transcranially five times a week for 8 min for a total of 4 weeks. The concentrations of OPN4 and monoamines were analyzed with Western blot and high-performance liquid chromatography (HPLC) techniques, respectively.

Results: Our results show that transcranial light illumination increases the amount of OPN4 in the hypothalamus and cerebellum. Additionally, the production of serotonin in the cortex was shown to decrease in the morning-light group.

Conclusions: With this study, we provide novel information on the effects of light administration through the skull on transmitters regulating circadian rhythmicity by showing that transcranial light affects molecules involved in circadian rhythmicity.

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Series: Journal of neurology research
ISSN: 1923-2845
ISSN-E: 1923-2853
ISSN-L: 1923-2845
Volume: 7
Issue: 3
Pages: 39 - 45
DOI: 10.14740/jnr427w
Type of Publication: A1 Journal article – refereed
Field of Science: 1184 Genetics, developmental biology, physiology
Funding: This work was supported by The Northern Ostrobothnia Health District, Valkee Inc., and Alfred Kordelinin foundation (grant number 150182).
Copyright information: © The authors. This article is distributed under the terms of the Creative Commons Attribution Non-Commercial 4.0 International License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.