FIGURE 3.

Effect of sex and dose on body weight (g) in female and male rats during extended-access self-administration and withdrawal. Mean (±SEM) body weight (g) at arrival, the end of self-administration training (training, days 3–5) just prior to extended-access self-administration, following approximately 5 days (ExA-1, days 4–6) and 10 days (ExA-2, days 9–10 or at the time of discontinuation of drug self-administration on withdrawal day 1) of extended-access self-administration, and during early (W1, days 2–4), intermediate (W2, days 6–9), and late withdrawal (W3, days 12, 13, and 14) for males and females in the 0.25 (n = 8 males, n = 9 females), 0.75 (n = 8 males, n = 9 females), 1.5 (n = 8 males, n = 8 females), and 3.0 (n = 8 males, n = 7 females) dose (μg/kg) conditions (A). These data are also plotted as percent change in body weight after approximately 5 (ExA-1) and 10 (ExA-2) days of extended-access self-administration relative to the end of training (training) just prior to extended-access self-administration (B) and during early, intermediate, and late withdrawal relative to the end of extended-access self-administration (ExA-2) just prior to withdrawal (C). (*) Significant effect of sex. (#) Significant difference from higher doses in males. (+) Significant difference between each of the withdrawal phases. (@) Significant difference from 0.25 μg/kg. (^) Significant difference from prewithdrawal body weight (versus 0 or no change).