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. Author manuscript; available in PMC: 2010 Dec 29.
Published in final edited form as: Curr Biol. 2009 Dec 10;19(24):2126–2132. doi: 10.1016/j.cub.2009.10.070

Figure 3. Ethanol Preference in Flies Exhibits Features of Addiction.

Figure 3

(A) Over time, naive flies developed ethanol preference when 300 μM quinine was added to the ethanol food throughout the assay. These flies had no preference on days 1–3 (p>.05), but had a positive preference on days 4 (p<.001) and 5 (p<.01). In the absence of ethanol, flies exhibited quinine aversion (p<.05 on all days, one sample t tests, n=16).

(B) Flies that had been drinking in the preference assay for 5 days continued to exhibit ethanol preference when 300 μM quinine was added to the ethanol food on the sixth day (p<.01, one sample t test, n=16), though this preference was decreased compared with controls lacking quinine. All 3 groups are significantly different from each other (***p<.001, one-way ANOVA with Tukey's post-test, n=16).

(C) After 5 days of drinking, flies were divided into two groups, one of which was deprived of ethanol access for two intermittent 1 day intervals (shaded). PI of the deprived group differed from the non-deprived group only during the deprivation periods (day 6 and day 8, ***p<.001). Post-deprivation PI did not differ from pre-deprivation PI (p>.05 for day 7 vs. day 5 and day 9 vs. day 7) or from the non-deprived group (p>.05 for day 7 and day 9).

(D) Same as (C) using a single 3 day deprivation. PI of the deprived group differed from the non-deprived group only during deprivation (days 6–8, *p<.05, ***p<.001). Post-deprivation PI did not differ from pre-deprivation PI or from the non-deprived group (p>.05).

In (C) and (D), one- or two-way repeated measures ANOVAs with Bonferroni's post-tests were used to compare values within the deprived group or between deprived and non-deprived groups, respectively. n=20 in (C) and n=10 in (D).