Undergraduate Honors Thesis

 

Effects of Corticosterone and Stress on Cry1 Expression in the Prefrontal Cortex of Male Rats, and Sex Differences in Stress-induced Cry1 Expression in the Hypothalamic Suprachiasmatic and Paraventricular Nuclei of Male and Female Rats Public Deposited

https://scholar.colorado.edu/concern/undergraduate_honors_theses/jw827c16t
Abstract
  • Promising evidence suggests that impaired circadian rhythms can lead to various mood disorders. Circadian rhythms are regulated by a master clock, the hypothalamic superchiasmatic nucleus (SCN), and its downstream circadian oscillators. Core clock genes compose the circadian clock through a system of feedback loops. A variety of inputs can modulate clock gene expression, such as glucocorticoid hormones, feeding cycles, temperature, and stress. In this study, I investigated the effects of acute stress on the expression of the core clock gene, Cry1, in the SCN, hypothalamic paraventricular nucleus (PVN), and prefrontal cortex (PFC) of rats maintained on a 12h/12h light-dark cycle. Stress has been shown to induce clock gene expression in various cell lines and tissues. In broad strokes the mechanism of stress induced clock gene expression is unknown. I hypothesized that glucocorticoid response elements (GRE’s) may play a role in stress induced clock gene expression. When bound by the glucocorticoid hormone-glucocorticoid receptor dimer, GRE’s promote transcription of genes. It has been shown that certain clock genes have GRE’s in their promoter regions. Based on this, I presumed that acute stress could increase clock gene expression in brain regions containing a high density of GR’s, if a functional GRE is present in the promoter region of the clock gene. Furthermore, I examined if there was a time of day effect of Cry1 mRNA in all three regions of interest, since clock gene expression is variable throughout a 24-hour period. I also examined whether there was a sex effect in the SCN and PVN, since there are gender differences in the magnitude of the CORT response to acute stress.
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  • 2016-01-01
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  • 2019-12-02
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