Control of Serotonergic Signaling by the Duodenum
Open Access
- Author:
- Ebert-Zavos, Elizabeth Paige
- Area of Honors:
- Animal Sciences
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Paul Allen Bartell, Thesis Supervisor
Paul Allen Bartell, Thesis Supervisor
Troy Ott, Thesis Honors Advisor - Keywords:
- serotonin
circadian
duodenum
chicken - Abstract:
- The main objective of my thesis was to determine how the circadian clock in the duodenum regulates serotonin synthesis and release in order to regulate circadian rhythms in digestive and skeletal systems. I hypothesized that a circadian clock exists in the duodenum and that this clock controls the biosynthesis and release of serotonin on a daily basis. In this series of experiments, duodenum and plasma from chickens were examined at different times of the day for the purpose of determining if: 1) the duodenum contains a functional molecular circadian clock; 2) the molecular circadian clock regulates genes that control serotonin biosynthesis; 3) the amount of serotonin in the duodenum varies across the day; and 4) serotonin profiles in blood are rhythmic. The circadian regulation of plasma serotonin by the duodenum may represent an additional biochemical signal in the blood encoding time and could be used by target tissues to indicate the status of nutrient absorption, in particular calcium. Serotonin has shown to cause bone degradation in mice and humans by affecting calcium regulation. Because serotonin affects duodenal absorption, the circadian molecular clock could control calcium bioavailability. If this clock can be regulated, it would be possible to modify other clocks to enable laying hens to produce eggs with thicker, stronger, eggshells and also reduce skeletal problems, such as osteoporosis.