Waterborne Risperidone Decreases Stress Response in Zebrafish

Abstract

The presence of drugs and their metabolites in surface waters and municipal effluents has been reported in several studies, but its impacts on aquatic organisms are not yet well understood. This study investigated the effects of acute exposure to the antipsychotic risperidone on the stress and behavioral responses in zebrafish. It became clear that intermediate concentration of risperidone inhibited the hypothalamic-pituitary-interrenal axis and displayed anxiolytic-like effects in zebrafish. The data presented here suggest that the presence of this antipsychotic in aquatic environments can alter neuroendocrine and behavior profiles in zebrafish.

Fig 1. Whole-body cortisol concentrations in zebrafish exposed to risperidone followed by an acute stress test and respective controls.

The values are expressed as the mean ± standard error of mean of 5–6 fish. Different small letters indicate significant group differences in each sampling time. The insert shows graphical demonstration of U-shaped dose response curve at the time of cortisol peak. S- and S+ refer to non-stressed and stressed fish, respectively.

Fig 2. Behavioral parameters of zebrafish in the novel tank test followed by an acute stress protocol.

Total distance (A), mean speed (B), crossings between compartments (C), absolute turn angle (D), time spent in the bottom (E), and time in the upper (F). The data are expressed as the mean ± standard error of mean of 5–6 fish. * = p<0.05 compared to Risp 0, S- group; ^# = p<0.05 compared to Rips 0, S+ group. S- and S+ refer to non-stressed and stressed fish, respectively.