Social context during drug exposure modulates behavioural effects in zebrafish

Abstract

Zebrafish are a popular model organism used to study anxiety behaviours and the impact of drugs that decrease (anxiolytic) or increase (anxiogenic) anxiety. There are, however, discrepancies in findings that are related to the social environment during exposure. Recent evidence suggests that the presence or absence of conspecifics (other zebrafish) during exposure differentially influences the effects of an anxiogenic when dosing and testing occur within the same context. No study has yet to look at whether the social environment during exposure influences the effectiveness of anxiolytic or anxiogenic substances when behaviours are later tested in the absence of conspecifics. The present study examined this by exposing adult zebrafish to either habitat water, ethanol (1.0 %; anxiolytic), or chondroitin sulfate (0.1 g/L; anxiogenic) while fish were either isolated or had view of conspecifics. When individually tested in the novel object approach test, these compounds had different effects depending on whether they were administered to fish in isolation, or within view of conspecifics. Ethanol and chondroitin sulfate were only found to have an effect on anxiety in fish who were isolated from conspecifics during exposure which could not be explained by differences in locomotion during dosing. A significant effect of social condition (isolated vs. in-view) was also found, with higher anxiety levels observed in fish that had visual access to conspecifics. These results suggest that social context during dosing influences the effectiveness of anxiolytic and anxiogenic compounds and should be considered in future behavioural studies.

Faculty Mentor: Trevor Hamilton

Department: Psychology (Honours)