Rapid tolerance to ethanol in ethanol sedation assaysData are from w1118 control female (A, C and E) and male (B, D and F) flies. A and B. Sedation time-courses from flies exposed once to vapor from water (W), exposed once to vapor from 50% ethanol (E), exposed to water vapor, allowed to recover for 4 hours, then exposed to vapor from 50% ethanol (WE), and exposed to vapor from 50% ethanol, allowed to recover for 4 hours, then exposed again to ethanol vapor (EE). Time and ethanol treatment had significant effects on the percentage of active flies and there was an interaction between time and ethanol treatment (individual two-way ANOVAs; time, p<0.0001; ethanol treatment, p<0.0001; interaction, p<0.0001, n=5–32 per treatment group). C and D. ST50 values derived from the data in panels A and B were significantly affected by ethanol treatment (one-way ANOVA, p<0.0001). ST50 values in EE flies were significantly different from those in E and WE flies (*Bonferroni’s, p<0.001), whereas ST50 values in E and WE flies were not statistically distinguishable (Bonferroni’s multiple comparison, n.s.). E and F. Internal ethanol concentrations increased with time of ethanol exposure, but were not significantly different in E and EE flies (individual two-way ANOVAs; time, p≤0.0002; E vs. EE, n.s.).
