Embryonic Cortisol Exposure Affects Development of Zebrafish Swimming Behavior

Abstract

Cortisol is the body’s primary stress hormone, and it plays a role in regulating the body through the hypothalamic-pituitary-adrenal (HPA) axis. Prenatal maternal stress may be related to behavior and mental health problems in offspring. How cortisol impacts neurodevelopment and corresponding functions is less understood. To assess the influence of cortisol on neurodevelopment, zebrafish embryos were exposed to different concentrations of cortisol from 6 hours postfertilization (hpf) to 5 days postfertilization (dpf). Zebrafish swimming behavior provides an output on neurodevelopmental issues that may be present despite normal morphological development. Previous results in lab found that for zebrafish exposed to cortisol for 5 days post-fertilization (dpf), 5 uM is the no observable adverse effect level (NOAEL) for morphological phenotypes. Here we tested if lower concentrations of cortisol affect development of 5 dpf zebrafish swimming behavior. We found that exposure to 0.5 µM and 5 uM cortisol reduces swim velocity in both light and dark contexts. These results suggest cortisol exposure at these concentrations can influence functional neurodevelopment in the absence of morphological phenotypes, which may be relevant to understanding the influence of prenatal stress on embryonic development.