Effects of retinal light input on circadian rhythm genes in the yellowtail clownfish (Amphiprion clarkii) as determined using LED light spectra

Abstract

The objective of this study was to test the effects of ophthalmectomy on the circadian rhythms in response to various wavelengths in yellowtail clownfish. The responses were evaluated by measuring rhodopsin (RH) and melatonin receptor 1 (MT1) mRNA and protein expression, and plasma melatonin levels. The RH, MT1 mRNA, and protein expression in ophthalmectomized fish were significantly lower than in intact fish. However, RH and MT1 mRNA and protein expression levels in green and blue light-emitting diode groups were similar between intact and ophthalmectomized fish. Furthermore, we found that the number of the RH-immunoreactive cells observed in the retina was almost in agreement with mRNA and protein expression patterns. These findings suggest that circadian rhythm involves the perception of light by the eye and the transduction of this signal through the circadian rhythm axis. Furthermore, short wavelengths lights may be most suitable for control of the circadian rhythm in fish.

Keywords:

• circadian rhythm
• light-emitting diodes
• melatonin receptor
• ophthalmectomy
• rhodopsin

Acknowledgements

This research was supported by the MSIP (Ministry of Science, ICT & Future Planning), Korea, under the ITRC (Information Technology Research Center) support program supervised by the NIPA (National IT Industry Promotion Agency) (NIPA-2013-H0301-13-2009).