FIGURE 2.

Effect of the different forms of Baclofen on alcohol operant self-administration in male and female rats. (A) The RS(±)-, the R(+)- and the S(−)-Baclofen were administered i.p. at the dose of 1.5 mg/kg 30 min prior to a 15-min session of alcohol self-administration. Each rat was its own control and received the 4 injections in random order. Results are expressed as Mean ± SEM of pure alcohol consumed in g/kg. *p < 0.05, **p < 0.01, ***p < 0.001, **** p < 0.0001, #### p < 0.0001 vs. R (+) and RS (±)-Baclofen, and $$$$ p < 0.0001 vs. RS(±)-Baclofen. (B) Cumulative lever presses observed after the injection of the different forms of Baclofen in male rats. Results are expressed as Mean ± SEM of the cumulative presses in 3-min bins over the 15 min session. ***p < 0.001 vs. Vehicle. (C) Cumulative lever presses observed after the injection of the different forms of Baclofen in female rats. Results are expressed as Mean ± SEM of the cumulative presses in 3-min bins over the 15 min session. **p < 0.01 vs. Vehicle. (D) Distribution of animal responses regarding sex (M for males and F for females on the left corner) and the treatments. Numbers inside the circle indicate the number of animals over the total of 15 rats. Percentages outside the circle express the amplitude of the variation in alcohol self-administration as compared to the vehicle treatment. Light grey represents a decrease in alcohol self-administration. The mild grey represents no change (between (−10 and +10%) as compared to vehicle. The dark grey represents an increase in alcohol self-administration as compared to vehicle. The results depicted in each of these 4 panels were provided by the same cohort of rats, 15 males and 15 females.