Title:Neurochemical and Behavioral Consequences of Ethanol and/or Caffeine
Exposure: Effects in Zebrafish and Rodents
Volume: 20
Issue: 3
Author(s): Carly L. Clayman and Victoria P. Connaughton*
Affiliation:
- Department of Biology and Center for Neuroscience and Behavior, American University, Washington, DC 20016, USA
Keywords:
Danio rerio, ethanol, caffeine, anxiety, adenosine, novel tank, scototaxis, shoaling.
Abstract: Zebrafish are increasingly being utilized to model the behavioral and neurochemical effects
of pharmaceuticals and, more recently, pharmaceutical interactions. Zebrafish models of stress
establish that both caffeine and ethanol influence anxiety, though few studies have implemented coadministration
to assess the interaction of anxiety and reward-seeking. Caffeine exposure in
zebrafish is teratogenic, causing developmental abnormalities in the cardiovascular, neuromuscular,
and nervous systems of embryos and larvae. Ethanol is also a teratogen and, as an anxiolytic substance,
may be able to offset the anxiogenic effects of caffeine. Co-exposure to caffeine and alcohol
impacts neuroanatomy and behavior in adolescent animal models, suggesting stimulant substances
may moderate the impact of alcohol on neural circuit development. Here, we review the literature
describing neuropharmacological and behavioral consequences of caffeine and/or alcohol exposure
in the zebrafish model, focusing on neurochemistry, locomotor effects, and behavioral assessments
of stress/anxiety as reported in adolescent/juvenile and adult animals. The purpose of this review is
twofold: (1) describe the work in zebrafish documenting the effects of ethanol and/or caffeine exposure
and (2) compare these zebrafish studies with comparable experiments in rodents. We focus on
specific neurochemical pathways (dopamine, serotonin, adenosine, GABA), anxiety-type behaviors
(assessed with a novel tank, thigmotaxis, shoaling), and locomotor changes resulting from both individual
and co-exposure. We compare findings in zebrafish with those in rodent models, revealing
similarities across species and identifying conservation of mechanisms that potentially reinforce coaddiction.