Honors Theses and Capstones

Comorbid effects of nicotine and ethanol on demand in rats: Ethanol demand may be influenced by the use of micotine

Taylor M. Gagne, University of New Hampshire - Main Campus


Nicotine and ethanol are two of the most commonly used psychoactive drugs in America, possibly do to its legal status. These two agents both work through the mesocorticolimbic system, also known as the reward pathway, which increases motivation to continue using and results in a dependency. While there are other factors that may affect the demand of these two drugs based in the sociological and psychological approaches, we focused on the biological mechanisms of the two substances working together. Due to the fact the ethanol is known to modulate the effect of other drugs, it is hypothesized that nicotine use will result in increased ethanol demand more so than the inverse. To test this, Wistar rats (n=19) were first trained to self administer a sucrose ethanol solution and then demand was assessed. Rats were then fitted with internal jugular catheters to be able to self administer nicotine, and demand was assessed in a similar manner. Finally rats were able to self administer ethanol while receiving non-contingent nicotine transfusions and vice versa before being allowed to self administer both simultaneously. It was shown that there was no relationship between the demand of the two drugs when taken separately, indicating any comorbid relationship would be related to the interaction of these two agents. However, to this point, the data from the comorbid section of the study has yet to be analyzed. It is expected that there will be a larger demand for either drug when taken concurrently compared to when each drug is taken separately, and. further, it is expected that the demand for ethanol while under the influence of nicotine will be greater than the inverse. Results from this project may add insight to the problem of comorbid cessation, indicating techniques that may be more successful than others based on which drug is stopped first, as one may exacerbate the dependency of the other, making cessation more difficult.