title: Circadian clock mediates light/dark preference in zebrafish (Danio rerio).
abstract: Zebrafish (Danio rerio) has been a widely used vertebrate animal model in developmental biology and behavioral neuroscience, but knowledge about some of its basic behaviors, for example, light/dark preference, is still controversial. Appropriate preference for light or dark environments can be crucial for an animal's survival, so we hypothesize that zebrafish may have its light/dark preference varied with the circadian clock. In this present work, we tested the hypothesis by recording the light/dark preference in a two-compartment tank continuously for over 60 h. We found that the light avoidance of fish generally increases with time from morning (8:00am) to midnight (2:00am), and then decreases with time from midnight (2:00am) to morning (8:00am), exhibiting a clear circadian-like trend in the light/dark preference. As melatonin can mediate circadian clock output and promote sleep in zebrafish, by adding extra melatonin at around 9:00am on the third day, the mean proportion of time fish spent in the dark area was increased significantly. Our results demonstrate that the circadian clock plays a significant role in regulating the light/dark preference in zebrafish, which provides valuable insights into understanding the metabolism mechanism underlying the neurobehavior, and facilitate further studies related to the neurobiology of normal and pathological behavior.
authors.affiliation: 1 School of Biotechnology and Food Engineering, Hefei University of Technology , Hefei, People's Republic of China .
authors.forename: Ju
authors.initials: J
authors.lastname: Wang
authors.forename: Changhong
authors.initials: C
authors.lastname: Liu
authors.forename: Fei
authors.initials: F
authors.lastname: Ma
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Bing
authors.initials: B
authors.lastname: Hu
authors.forename: Lei
authors.initials: L
authors.lastname: Zheng
mesh_terms: D000818:Animals; D057906:Circadian Clocks / Q000187:drug effects / Q000502:physiology*; D005260:Female; D008027:Light; D008297:Male; D008550:Melatonin / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects; D012890:Sleep / Q000187:drug effects / Q000502:physiology; D015027:Zebrafish / Q000502:physiology*
chemical_list: D008550:Melatonin