Acute Net Stressor Increases Whole-Body Cortisol Levels Without Altering Whole-Brain Monoamines in Zebrafish

Recent studies have started to examine the neurochemical and hormonal basis of behavior in zebrafish by examining biological correlates postmortem. However, it is unknown whether stress involved with experimental handling prior to euthanizing animals will have an impact on subsequent biological measures. In the current study, we expose zebrafish to a short net handling stressor (30 s) and examine the levels of monoamine neurotransmitters (dopamine, serotonin, and their metabolites) and whole-body cortisol at different intervals poststressor (0, 1, 5, 10, and 15 min). We report a time-dependent increase in the levels of cortisol, but no alterations in the levels of dopamine, DOPAC (dopamine's metabolite), serotonin, or 5HIAA (serotonin's metabolite) poststressor. The results demonstrate cortisol levels are more responsive to this type of stimulus compared with neurochemical measures.