Novel findings to aid in alcohol use disorder research : ethanol vapor and the ventral tegmental area

The high prevalence of alcohol use disorder continues to impact individuals by heightening stress, anxiety and disrupting cognitive tasks (Morrow and Creese, 1986). Ethanol affects several neuromodulator systems, exerting its effects within the central nervous system (Deehan et al., 2013). One known effect of ethanol is its impact on the mesocorticolimbic system and related circuits, including the ventral tegmental area and its involvement in the regulation of motivation and goal-directed behavior (Doyon et al., 2020). The neurotransmitter norepinephrine has also been linked to mood stabilization, alertness, as well as the endocrine and autonomic nervous systems (Vazey et al., 2018). Additional issues remain to be explored, such as the interaction between norepinephrine signaling and other neuromodulators, and a better mechanistic understanding of ethanol withdrawal (Kushner et al., 2000; Skelly and Weiner 2014; Fredriksson et al., 2015; Becker and Koob, 2016; Petrakis et al., 2016). In order to increase our understanding of alcohol use disorder I carried out two experiments throughout the course of my thesis. We conducted an ethanol vapor study showing that we were able to successfully induce alcohol dependence and withdrawal through a short ten-day vapor exposure model in Long Evans male rats. Lastly, we created a time course of ethanol in the ventral tegmental area through gas chromatography analysis, also using microdialysis. In the appendix we also show pilot data from a study were we closely examined the estrous cycle in female rats that underwent surgery to place an intracranial guide cannula for microdialysis experiments. We found the possible surgical effects that can halt cycling and ultimately affect data looking at differences between males and females in alcohol dependance and withdrawal, however more experiments are necessary to make a precise conclusion. Findings from these three experiments can be used to continue the advancement of alcohol use disorder research in different ways.