Recent advances with a novel model organism: Alcohol tolerance and sensitization in zebrafish (Danio rerio)

Abstract

Alcohol abuse and dependence is a rapidly growing problem with few treatment options available. The zebrafish has become a popular animal model for behavioural neuroscience. This species may be appropriate for investigating the effects of alcohol on the vertebrate brain. In the current review, we examine the literature by discussing how alcohol alters behaviour in zebrafish and how it may affect biological correlates. We focus on two phenomena that are often examined in the context of alcohol-induced neuroplasticity. Alcohol tolerance (a progressive decrease in the effect of alcohol over time) is often observed following continuous (chronic) exposure to low concentrations of alcohol. Alcohol sensitization also called reverse tolerance (a progressive increase in the effect of alcohol over time) is often observed following repeated discrete exposures to higher concentrations of alcohol. These two phenomena may underlie the development and maintenance of alcohol addiction. The phenotypical characterization of these responses in zebrafish may be the first important steps in establishing this species as a tool for the analysis of the molecular and neurobiological mechanisms underlying human alcohol addiction.

Extreme anoxia tolerance in crucian carp and goldfish through neofunctionalization of duplicated genes creating a new ethanol-producing pyruvate decarboxylase pathway

“…Cyprinids like the goldfish have a long history of use in ethanol toxicity studies 34 and zebrafish are emerging model systems for the study of alcohol tolerance and sensitization, and foetal alcohol syndrome 35 , 36 . Members of the Carassius lineage are naturally exposed to elevated tissue ethanol concentrations reaching up to 7 µmol/g in red muscle during anoxia for up to 4–5 months of the year 8 , and we suggest that they also hold promise as a model systems for the study of molecular mechanisms protecting against chronic ethanol exposure.…”

Long-term contextual memory in infant rats as evidenced by an ethanol conditioned tolerance procedure

“…Results from Experiments 1a and 1b show that infant female rats can also display sensitization induced by ethanol, although the conditions that favor the expression of this ethanol effect, for example, the testing dose of ethanol, vary slightly between males and females. The mechanisms underlying both ethanol effectstolerance and sensitizationhave been widely studied and they appear to be independent processes (Phillips et al, 1997, Siegel et al, 2000, Pietrzykowski and Treistman, 2008, Phillips, 2011, Tran and Gerlai, 2014. With our experimental setting both effects resulted from application of the same training protocol, but their expression was dependent on when and where testing was carried out and on the age of the subjects.…”

Coffee time: Low caffeine dose promotes attention and focus in zebrafish

“…To obtain these concentrations, the specific amount of caffeine powder (Sigma-Aldrich #cat C0507) was diluted in the system water. The doses were gradually increased in order to prevent animal deaths (Tran & Gerlai, 2014), starting with 5 mg/L and increasing by 50% every two days until the desired dosage was reached (10 or 50 mg/L). Caffeine exposure occurred for 60 min before and during the training/test sessions.…”