Differential behavioral effects of ethanol pre-exposure in male and female zebrafish (Danio rerio)

Alcohol exposure in adolescence is a contributing factor toward reward-seeking behavior in adulthood. This reward-seeking behavior is assessed in animal models using the conditioned place preference (CPP) paradigm. In this study, ethanol-induced change in time spent by zebrafish on the initially non-preferred tank side was studied by conditioning adult zebrafish to ethanol dissolved in water (0.00% 1.00%; 1.25%; 1.50%; 1.60%; 1.75% vol/vol) paired with an initially non-preferred environment. Following a single conditioning cycle, fish swam unrestricted in the CPP chamber to assess changes in preference. Daily 20-min pre-exposure to ethanol for 1 week during the juvenile stage starting at either 20 days post fertilization (dpf) or 40 dpf altered percent time spent on the ethanol-paired side in adulthood in a dose-dependent and sex-dependent manner. The results suggest that male and female zebrafish are an effective model in which to investigate behavioral correlates of ethanol-induced changes in neural circuits implicated in reward and anxiety.