Undergraduate Honors Theses

Thesis Defended

Spring 2016

Document Type


Type of Thesis

Departmental Honors


Molecular, Cellular, & Developmental Biology

First Advisor

Dr. Ryan Bachtell

Second Advisor

Dr. Jennifer Martin

Third Advisor

Dr. Jerry Rudy


Alcohol is a drug commonly co-administered with other drugs like the psychostimulant methamphetamine. Both alcohol and methamphetamine target the mesocorticolimbic reward system of the brain through distinct mechanisms of action and the concurrent use of methamphetamine and alcohol likely has complex neurobiological consequences that could cause a variety of negative side effects. The present study serves to examine the way these two powerful drugs of abuse influence the consumption of one another. Alcohol-preferring rats or “P rats” were used as an animal model and given access to a two-bottle alcohol choice procedure in the home cage to measure alcohol consumption and preference. Methamphetamine intake was measured by training animals to self-administer methamphetamine in an operant conditioning chamber. Our study found that while alcohol consumption has no significant effect on the self-administration of methamphetamine, methamphetamine self-administration decreases the consumption and preference for alcohol. This effect was observed through all procedural variations and suggests an antagonistic effect of methamphetamine use on alcohol reward. Adenosine signaling serves as a modulator for dopamine in the reward pathway and helps to attenuate reward signaling at physiological levels. To identify a possible mechanism behind the behavioral effects we’d found, we examined the presence of adenosine signaling proteins such as ENT1 proteins and A1 receptors in animals taking methamphetamine. Our study found an increase in ENT1 protein and a decrease in A1 receptors in animals taking methamphetamine which suggests a role for adenosine signaling in the effect of methamphetamine on alcohol consumption and preference. Our experimental findings are some of the first insights into the neurobiological aspects behind the drug interaction of methamphetamine and alcohol, and are contributions to the knowledge of the chemical basis of drug addiction.