Acute Stress Effects over Time on Gene Expression Patterns in the Male Zebrafish (Danio rerio) Brain.

Studies aiming at evaluating specific changes in gene expression in male zebrafish brains as a consequence of the exposure to acute stressors have not been conducted so far. However, the identification of genes that specifically respond to certain stress situations would improve our understanding of stress responses in fish. For this, a stress trial with acutely stressed male zebrafish was conducted, aiming at identifying relevant differences in gene expressions in different brain parts over time. The qPCR results showed changes of gene expression of genes belonging to the immediate early genes and the stress axis, as well as genes regulating the appetite or serotonergic and dopaminergic pathways in the different brain parts across all treatment groups. Several genes, including urotensin 1, corticotropin-releasing hormone-binding protein, and succinate dehydrogenase, were identified as strongly contributing to the outcome of stress regulation, but these genes considerably differ for each brain part. Thus, the study confirmed that the gene expression patterns strongly depend on the species that is investigated, the quality of the stressor, and the time point of investigation. Furthermore, the current results evaluating only the responses of males will allow the evaluation of gender-specific responses to stress in this fish species in the future.