Indiana University-Purdue University Indianapolis (IUPUI) / Tolerance is a diagnostic criterion for alcohol use disorder (AUD) and dependence and is often measured metabolically or behaviorally by comparing blood ethanol concentrations (BEC) or locomotor performance to an ethanol (EtOH) challenge before and after a drinking history, respectively. To explore another aspect of chronic behavioral tolerance in a family history positive (FH+) model of AUD, crossed High Alcohol Preferring (cHAP) mice were allowed to respond instrumentally for an EtOH reinforcer after either a five-week history of continuous home cage two-bottle choice (2BC) drinking or a concurrent five-week water-drinking period. Additionally, some of these animals were placed back into the operant box after home cage drinking histories to respond in extinction, allowing for the quantification of alcohol-motivated seeking alone in the absence of EtOH taking and its intoxicating effects. The results demonstrate that an alcohol history does not lead to a subsequent increase in active lever responding or inactive lever responding when compared to water-drinking controls. However, female cHAP mice with an EtOH-drinking history respond more on the inactive lever in extinction compared to water controls, suggesting that home cage EtOH history potentiates variation in responding in extinction. Overall, female mice responded more on the active lever and drank more alcohol in the reinforced condition, but again, there was not an effect of drinking history on this sex-specific effect. Together these results suggest that while female cHAPs, regardless of drinking history, are more motivated to work to drink EtOH, reinforced and non-reinforced instrumental responding are not reliable readouts for tolerance in cHAP mice compared to other endpoints such as drinking in the dark (DID) assays.

<p>Tolerance is a diagnostic criterion for alcohol use disorder (AUD) and dependence and is often measured metabolically or behaviorally by comparing blood ethanol concentrations (BEC) or locomotor performance to an ethanol (EtOH) challenge before and after a drinking history, respectively. To explore another aspect of chronic behavioral tolerance in a family history positive (FH+) model of AUD, crossed High Alcohol Preferring (cHAP) mice were allowed to respond instrumentally for an EtOH reinforcer after either a five-week history of continuous home cage two-bottle choice (2BC) drinking or a concurrent five-week water-drinking period. Additionally, some of these animals were placed back into the operant box after home cage drinking histories to respond in extinction, allowing for the quantification of alcohol-motivated seeking alone in the absence of EtOH taking and its intoxicating effects. The results demonstrate that an alcohol history does not lead to a subsequent increase in active lever responding or inactive lever responding when compared to water-drinking controls. However, female cHAP mice with an EtOH-drinking history respond more on the inactive lever in extinction compared to water controls, suggesting that home cage EtOH history potentiates variation in responding in extinction. Overall, female mice responded more on the active lever and drank more alcohol in the reinforced condition, but again, there was not an effect of drinking history on this sex-specific effect. Together these results suggest that while female cHAPs, regardless of drinking history, are more motivated to work to drink EtOH, reinforced and non-reinforced instrumental responding are not reliable readouts for tolerance in cHAP mice compared to other endpoints such as drinking in the dark (DID) assays.</p>

<p>Evolutionary innovations, at the molecular level, represent the novel establishment of regulation networks among previously unconnected genes. Understanding the cellular and molecular mechanisms that underlies the development of such innovations is of central importance in evolutionary-developmental research (evo-devo). The sex comb of <em>Drosophila</em> is an excellent model to study the molecular basis of evolutionary innovations. Highline and Lowline are two artificial selected <em>D. melanogaster</em> lines differing in the number of sex comb bristles. It was expected that the “cross-regulation loop” between two transcription factors, <em>Doublesex</em> male isoform (DSX^M) and <em>Sexcombs reduced</em> (SCR), evolves rapidly and promotes the morphological evolution of sex combs. We used immunofluorescent technique (antibody staining) to compare the expression of DSX^M and SCR in the forelegs of three different lines (Highline, Wildtype and Lowline). We hypothesized that artificial selection will increase expression of DSX^Mand SCR in the Highline and reduce expression in the Lowline. The fluorescent pictures of antibody staining experiments indicate that the expression region of DSX^M in the Highline is significantly higher than the expression region in the Lowline, and the expression levels of SCR has minor difference among the three lines. DSX^M expression is altered by the artificial selection, but SCR expression is not. The influence of artificial selection appears to have been constrained by development. Our investigation provides an approach to test the validity of the models of cross-regulation s between SCR and DSX^M during development.</p> / Master of Science (MSc)