The Effects of Short Term Glucocorticoid Exposure on Hippocampal Neuronal Structure and Signaling Pathways in Female Rats

Pacosz, Julia
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University of Guelph

The hippocampus plays a critical role in learning, memory and mood regulation. Estradiol and glucocorticoids affect pyramidal neuron dendritic morphology in hippocampal regions CA1 and CA3, which is associated with altered cognition and behaviour. Previous work in our laboratory demonstrated that stress of surgery induced significant changes in dendritic arborization in males. Dexamethasone treatment in males, that mimics short-term stress, indicated that glucocorticoids play a significant role in stress-induced dendritic remodeling. However, the effects of stress on hippocampal neuronal morphology in females with naturally cycling estradiol remain uncharacterized. The findings of this thesis suggest that dexamethasone treatment induces significant dendritic and spine changes in CA1 and CA3. These neuronal effects are accompanied by enhancements in ERK, DUSP6, and JNK signaling proteins. In conclusion, the results indicate that the response to short-term glucocorticoids may be proliferative in the female hippocampus, evidenced by augmentations in neuronal morphology and underlying cell-signaling mechanisms.

Glucocorticoids, Estradiol, Hippocampus, CA1, CA3, Corticosterone, Dexamethasone, Dendritic spine density, Dendritic remodeling, Dendritic branching, Dendritic length, Estrous cycle, Females, Cell signaling, MAPK, ERK phosphorylation, JNK phosphorylation, DUSP6