Honors College Theses

Publication Date



Biology (B.S.B.)

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Faculty Mentor

Dr. Robert Mans


Postural orthostatic tachycardia syndrome (POTS) is a chronic illness categorized by the dysregulation of the autonomic nervous system (ANS), and affected individuals can experience fatigue, headaches, heart palpitations, dysregulation of blood pressure, and chest pain, among other symptoms. The ANS is tightly regulated by the internal 24-hour biological clock known widely as the circadian rhythm and is generated by the suprachiasmatic nucleus of the brain. The circadian rhythm regulates the function of every cell in the body, including those of the cardiac system. The current study was conducted to determine if alterations in circadian cycles would affect cardiac function in a zebrafish model. Fish were housed in light-isolated boxes equipped with lights and timers and were subjected to a 4-day acclimation period. After acclimation, the control fish maintained a standard light/dark cycle of 14 hours light/10 hours dark for 7 days. Experimental fish were subject to two protocols: 18 hours/10 hours light/dark cycle and 19 hours/5 hours light/dark cycle for 7 days following acclimation. Electrocardiogram (ECG) testing of zebrafish hearts was performed under anesthesia. The findings indicate that altered light cycles caused an increase in the duration of the T wave, QRS complex and the P wave of the ECG.