Date on Master's Thesis/Doctoral Dissertation
Physiology and Biophysics
Physiology and Biophysics, PhD
Committee Co-Chair (if applicable)
Dysphagia; deglutition; respiration; buprenorphine; serotonin
This dissertation presents a series of studies examining mechanisms of deglutition and respiration, and how these vital processes are impacted by opioids. The experiments in Chapter Two investigated the role of the upper esophagus in airway protection through systematic activation of pharyngeal and esophageal mechanoreceptors in a cat electromyography model. Chapter Three compared effects of opioid administration on breathing and swallowing between male and female rats, and found that females are more susceptible to opioid-induced depression of breathing and swallow than males. Findings from Chapters Two and Three led to the development of a translational model of opioid-induced dysphagia using videofluoroscopy. Chapter Four demonstrated that opioid administration resulted in a significant decline in airway protection during swallow in freely feeding, unrestrained cats. This work has advanced knowledge of the regulation of the upper aerodigestive tract, and its dual roles in breathing and swallowing. An improved understanding of the neural control of deglutition will facilitate the development of effective treatments for dysphagia. This dissertation includes the first study to compare effects of opioids on pharyngeal swallow between sexes, and provides mechanistic and clinically-translatable insights into opioid-induced dysphagia. Elucidating the actions of opioids on the brainstem breathing and swallowing networks will aid the prevention and treatment of opioid-induced respiratory depression and dysphagia related complications such as aspiration pneumonia.
Frazure, Michael, "Swallow, breathing and survival: sex-specific effects of opioids." (2023). Electronic Theses and Dissertations. Paper 4145.