Fig. 2: Sex differences in addiction-like behaviors. | Neuropsychopharmacology

Fig. 2: Sex differences in addiction-like behaviors.

From: Large-scale behavioral characterization of oxycodone self-administration in heterogeneous stock rats reveals initial analgesic effects are associated with addiction-like behaviors

Fig. 2

A Number of oxycodone infusions (150 μg/kg/infusion) during the first hour of short-access (ShA; 2 h/day) and long-access (LgA; 12 h/day) oxycodone self-administration in male and female HS rats (N = 542). Females exhibited greater escalation from day 6 of LgA onward (***p < 0.01 vs LgA 1 and ##p < 0.01 vs males, two-way ANOVA with Bonferroni post hoc tests). B Violin plot depicting the number of oxycodone infusions under progressive ratio (PR) testing after ShA and LgA phases in male and female HS rats (N = 542; ***p < 0.01 vs ShA, ##p < 0.01 vs males, two-way ANOVA with Bonferroni post hoc tests). C Development of tolerance to oxycodone’s analgesic effects. Tail withdrawal thresholds (in seconds) measured via the tail immersion test at baseline (BSL), after two oxycodone infusions pre-extended-access self-administration (Oxy-pre-SA), and post- extended-access self-administration (Oxy post-SA) in male and female HS rats (N = 542, ***p < 0.001 vs BSL and ###p < 0.001 vs Oxy-pre-SA, one-way ANOVA with Bonferroni post hoc tests). D Development of withdrawal-induced hyperalgesia in male and female HS rats. Data represent percent change from baseline in paw withdrawal force (g) measured via the von Frey test before and after extended-access oxycodone self-administration (N = 542; ***p < 0.001 vs BSL, paired t-test).

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