Towards a Better Understanding of Zebrafish Sleep Behavior

Sleep serves many vital functions in humans, ranging from energy restoration to memory consolidation and information integration. Sleep deprivation is linked to worsened physiological states and psychological conditions. Zebrafish are an emerging model in neurobehavioral research and have recently demonstrated great utility in the study of sleep. This teleost species possesses several of the same neurotransmitter and neuropeptide systems that are involved in the regulation of sleep and waking rhythms in higher order mammals. Previous study of these animals has revealed a differential gene and proteomic expression following sleep deprivation through changes in environmental stimuli. The present study sought to expand on the current understanding of sleep behavior in this animal. The behavior of adult zebrafish was evaluated as they were exposed to varying environmental and pharmacological interventions. Animals were exposed to one of three conditions: (1) sustained darkness, (2) sustained brightness, and (3) sustained bright conditions, paired with the administration of an adenosine antagonist. The presentation of bright lights was effective in disrupting sleep rhythms. The administration of caffeine paired with the presentation of bright lights was the most effective method of reducing sleep in the zebrafish. Following sleep disruption animals were tested in the novel tank test or the open field task to elucidate the effects of sleep rhythm disruption on anxiety. We expand on the current interaction of sleep and anxiety and report no increases in anxiety like behaviors in the zebrafish following any of the environmental or pharmacological interventions