Publication Cover
Chronobiology International
The Journal of Biological and Medical Rhythm Research
Volume 36, 2019 - Issue 7
878
Views
11
CrossRef citations to date
0
Altmetric
Original Articles

Red white and blue – bright light effects in a diurnal rodent model for seasonal affective disorder

, , , , , & show all
Pages 919-926 | Received 26 Jan 2019, Accepted 12 Mar 2019, Published online: 15 Apr 2019
 

ABSTRACT

Despite the common use of bright light exposure for treatment of seasonal affective disorder (SAD), the underlying biology of the therapeutic effect is not clear. Moreover, there is a debate regarding the most efficacious wavelength of light for treatment. Whereas according to the traditional approach full-spectrum light is used, recent studies suggest that the critical wavelengths are within the range of blue light (460 and 484 nm). Our previous work shows that when diurnal rodents are maintained under short photoperiod they develop depression- and anxiety-like behavioral phenotype that is ameliorated by treatment with wide-spectrum bright light exposure (2500 lux at the cage, 5000 K). Our current study compares the effect of bright wide-spectrum (3,000 lux, wavelength 420- 780 nm, 5487 K), blue (1,300 lux, wavelength 420-530 nm) and red light (1,300 lux, wavelength range 600-780 nm) exposure in the fat sand rat (Psammomys Obesus) model of SAD. We report results of experiments with six groups of sand rats that were kept under various photoperiods and light treatments, and subjected to behavioral tests related to emotions: forced swim test, elevated plus maze and social interactions. Exposure to either intense wide-spectrum white light or to blue light equally ameliorated depression-like behavior whereas red light had no effect. Bright wide-spectrum white light treatment had no effect on animals maintained under neutral photoperiod, meaning that light exposure was only effective in the pathological-like state. The resemblance between the effects of bright white light and blue light suggests that intrinsically photosensitive retinal ganglion cells (ipRGCs) are involved in the underlying biology of SAD and light therapy.

Acknowledgments

This research was supported by the Israel Science Foundation (grant No. 866/17) and The Israel Science Foundation (grant No. 2730/16) as part of the ISF-UCG joint program. The authors wish to thank Or mekuvan (https://www.ormekuvan.co.il/), a nonprofit organization promoting sustainable and responsible use of light, and especially Gilad Gozni, for their help in building the light treatment system.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the Israel Science Foundation [866/17,ISF-UCG 2730/16].

Log in via your institution

Log in to Taylor & Francis Online

PDF download + Online access

  • 48 hours access to article PDF & online version
  • Article PDF can be downloaded
  • Article PDF can be printed
USD 61.00 Add to cart

Issue Purchase

  • 30 days online access to complete issue
  • Article PDFs can be downloaded
  • Article PDFs can be printed
USD 489.00 Add to cart

* Local tax will be added as applicable

Related Research

People also read lists articles that other readers of this article have read.

Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine.

Cited by lists all citing articles based on Crossref citations.
Articles with the Crossref icon will open in a new tab.