Glucocorticoids are steroid hormones vital to development and many physiological responses. The body’s primary glucocorticoid, cortisol, is released in response to stress and binds to two receptors: mineralocorticoid (MR) and glucocorticoid receptors (GR). Excess prenatal exposure to glucocorticoids has been linked to adverse effects on neurodevelopment. Previous work in the lab found that an increase in embryonic exposure to cortisol resulted in decreased swim behavior in zebrafish larvae 5 days post-fertilization (dpf). The goal of this study was to identify how selective MR exposure would affect behavior in larval zebrafish using deoxycorticosterone (DOC), a natural precursor to cortisol that binds to MR. Zebrafish embryos were treated with decreasing concentrations of DOC (1 µM, 0.3 µM, and 0.1 µM) at 4-6 hours post-fertilization (hpf) in a 12-well plate. Larvae were transferred at 5dpf to a 96-well plate and assayed using a commercial motor tracking system (Noldus DanioVision). Initial results indicate that the swim velocities for larvae exposed to 0.3 µM DOC were higher than control groups in the first dark cycle, but no other significant differences were observed. By investigating how DOC affects neurodevelopment in zebrafish, these results can inform future studies on the role of MR agonists in development.
