Date of Award


Publication Type


Degree Name



Integrative Biology


B. Zielinski


Chemosensation, Electrophysiology, Fish, Petromyzon, Sea iampreys, Taste



Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.


The sea lamprey is a basal vertebrate, and the oldest extant species with taste buds. The objective of this thesis was to study the chemosensory responses from the sea lamprey’s pharynx, which is located caudal to oral cavity and medial to seven lateral brachiopores. The pharynx contains taste buds that detect and respond to tastants to inform lampreys about gustatory factors in the environment. The location of these taste buds along the lateral surface of the pharynx was first determined using scanning electron microscopy. Then using electrophysiology, our recordings from these pharyngeal regions containing taste buds picked up responses from the nerve fibers after stimulation using a variety of compounds such as sucrose, NaCl, alanine, arginine, denatonium, ATP and bile acids. Each region of the pharynx between the seven brachiopores was tested and was responsive to the application of a carefully picked set of taste stimulants, indicating no regional differences in the chemosensory properties of the pharynx. Additionally, larval responses to samples collected from the natural stream burrowing sites were tested and were stimulatory to the larval lamprey’s pharynx. This thesis provides insight into the tastants and gustatory system of a basal vertebrate that posseses a taste system that derived from ancestral jawless vertebrates.