(full paper is archived in the Miller Library)
Title: Predator stress induces down-regulation of adult neurogenesis in zebrafish
Student Author(s): Mayer, Joseph
Faculty Advisor(s): Thompson, Stuart
Location: Final Papers Biology l75H
Date: June 2003
Abstract: Exposure of teleost fish to predator stress has been shown to elevate plasma cortisol levels. Consequently, we examined the effects of predator stress (albino oscars) on neurogenesis in adult zebrafish. To find out how stress affects adult neurogenesis in the zebrafish, we subjected zebrafish to acute or chronic predator stress and assessed the proliferation of newly born cells in the optic tectum and cerebellum. These regions are known to have measurable rates of cell proliferation. Stereologic analyses of the number of 5-bromo-2’ deoxyuridine (BrdU) labeled cells revealed that 1 exposure of zebrafish to a predator (acute stress) did not change cell proliferation in the optic tectum or the cerebellum. However, three day repeated predator stress (chronic stress) significantly reduced cell proliferation, by 37% in the optic tectum, while having no significant effect in the cerebellum. A comparison between non-stressed zebrafish optic tectum and cerebellum revealed no significant regional difference in cell proliferation rate. These findings suggest that stressful experiences may down-regulate adult neurogenesis in certain regions of the zebrafish brain, similar to stress induced neurogenesis effects in mammals and birds. This study presents the zebrafish as a unique new model for understanding adult neurogenesis and its underlying molecular mechanisms.