To control for differences in animal weight that could influence operant ethanol self-administration levels, lever presses were converted to g/kg ethanol consumption for all analyses in the present manuscript. To confirm that intermittent ethanol vapor induced a dependence-like phenotype, a mixed model two-way analysis of variance (ANOVA) was conducted on ethanol consumption data from the four post-induction period sessions for air- and ethanol vapor-exposed animals. Although mixed-model ANOVAs are used in later analyses of MMP inhibition, those ANOVAS did not include a comparison of air- and vapor-exposed animal data as the initial demonstration of escalation did (Fig. 2), but instead focused exclusively on comparisons of vapor-exposed animals with or without acute or chronic MMP inhibition.
