Murray State Theses and Dissertations

Abstract

THE EFFECTS OF EARLY EXPOSURE TO PRESCRIPTION/ILLICIT DRUGS AND DRUG METABOLITES ON LARVAL ZEBRAFISH BEHAVIORAL AND MOTOR FUNCTION DEVELOPMENT

A Thesis Presented to the Faculty of the Department of Biology

Murray State University

Murray, Kentucky

In Partial Fulfillment of the Requirements for the Degree of Masters In Science

By Jacob Thomas, B.S., Murray State University

December 2024

Acknowledgements

Brandon Capps, who pretty much did a whole third of the legwork on this project and saved me lots of headaches;

Chandler Maddox, one of the University of Kentucky’s finest undergrads who came in from the top rope with a folding chair (a summer of volunteering to perform data analysis), and without whom I probably wouldn’t have gotten this done on time;

Dena Weinberger, who took a chance on me despite being the world’s worst neurobiology and physiology student and fostered my growth as a scholar over the past 3 years;

The University of Kentucky Predictive Analytics and Data Science Hub, who helped make sense of the numerous statistical analyses used here;


My wonderful wife, Violet Hayes Thomas, who kept me from going insane and quitting halfway through the project despite numerous protestations;

And most of all: the humble zebrafish, who in spite of spending weeks at a time refusing to procreate are pretty much the ONLY reason I have a project in the first place!

Abstract

The rise of prescription and illicit psychoactive drug use in the 21st century has brought along with it a host of effects, ranging from sociological to psychological to even environmental. While the problems caused by use itself are well understood at this point, it is the byproducts of use that have received less attention. The drug metabolites and unaltered drugs excreted after use have to end up somewhere, typically in municipal water systems. Waste treatment facilities are not designed to remove or treat these compounds, and as such they will make their way out into the watershed where their long term environmental impact is not understood. Many of these drugs and their metabolites have overlapping targets, leading to potential synergism of effects. To understand the potential risks of this type of exposure, zebrafish larvae were dosed with a cocktail of psychoactive drugs and byproducts with concentrations based on worst-case scenario samples taken from waste treatment facilities, as well as exemplary stimulant and depressant drugs, and subjected to several assays intended to identify changes in motor function and stereotypical behaviors when compared to control larvae. Several differences were detected between control and dosed larvae, but further testing is required to explore the root cause and to expand the testing paradigm to detect behavioral and sensory alterations not explored in this initial analysis.

Year manuscript completed

2024

Year degree awarded

2024

Author's Keywords

zebrafish, drug exposure, behavior assay, larval, gene expression

Degree Awarded

Master of Science

Department

Biology

College/School

Jesse D. Jones College of Science, Engineering and Technology

Thesis Advisor

Dena Weinberger

Committee Chair

Dena Weinberger

Committee Member

Laura Sullivan-Beckers

Committee Member

Gary ZeRuth

Document Type

Thesis

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Available for download on Sunday, November 30, 2025

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