Understanding sex and populational differences in spatio-temporal exploration patterns and homebase dynamics of zebrafish following repeated ethanol exposure.

Ethanol (EtOH) is one of the most widely consumed substance, affecting neurobehavioral functions depending on multiple environmental and biological factors. Although EtOH modulates zebrafish (Danio rerio) anxiety-like behaviors in novelty-based paradigms, the potential role of biological sex and populational variability in the exploratory dynamics in the open field test (OFT) is unknown. Here, we explored whether a repeated EtOH exposure protocol modulates the spatio-temporal exploration and homebase-related parameters in a population- and sex-dependent manner. Male and female fish from the short-fin (SF) and leopard (LEO) phenotypes were exposed to EtOH for 7 days (1 % v/v, 20 min per day). On the 8th day, the OFT was performed to assess locomotor and exploratory behaviors. We verified significant populational differences in the baseline spatio-temporal exploration patterns, supporting a pronounced anxiety in LEO with a higher homebase index compared to SF. We also found sex-dependent differences in EtOH sensitivity, where SF was more sensitive to EtOH, especially in females, which showed marked alterations in thigmotaxis and homebase occupancy. Conversely, only LEO female subjects showed increased center occupancy following EtOH. Principal component analysis (PCA) showed the main components that explained data variability, which were sex- and population-dependent. Overall, our novel findings support the utility of zebrafish-based models to assess how EtOH influences the exploratory profile in the OFT, as well as to elucidate potential differences of sex and population in the neurobehavioral responses of alcohol exposure in a translational perspective.