Fig. 6

MDMA and oxytocin receptor agonists produce prosocial effects in fish. To assess how 3-week-old fish respond to synthetic (MDMA) and endogenous (WAY-267464) empathogens, a three-chambered setup was utilised. Results showed that MDMA at the lower tested dose of 0.5??M significantly increased the social preference index (a) and the doses of 1.0 and 5.0??M increased the percentage of entries into the social zone (b), indicating its prosocial activity. The effect was not due to changes in fish locomotion (c). Similarly, WAY-267464, an oxytocin receptor agonist, was able to promote prosocial behaviour, as shown by an increase in social preference index (d) and an increase in the percentage of entries into the social zone (e) at the highest tested dose of 100??M. The compound had no effect on overall fish movement (f). By contrast, the oxytocin receptor antagonist, L-368,899, had no effect on the social preference index (g) nor entries to the social zone (h) and locomotion of fish (i). Data were analysed using a one-way analysis of variance followed by Dunnett?s post hoc test (a?d, f?h). Kruskal?Wallis test with Dunn?s post hoc was used for datasets that failed normality testing or had significantly different variances (e, i). The confidence limit of *p?