Skip to main content
. Author manuscript; available in PMC: 2022 Dec 1.
Published in final edited form as: Exp Clin Psychopharmacol. 2020 Apr 16;29(6):636–649. doi: 10.1037/pha0000375

Figure 1. Heroin Self-Administration.

Figure 1.

(A) Male and female rats showed increased heroin intake across sessions, comparing infusions earned in each session versus session 1. When broken down by sex, both females (B) and males (C) showed discrimination between the active and inactive levers across sessions. (D) The rate of heroin intake increased significantly faster in males than in females. (E) Total number of heroin infusions across all 14 self-administration sessions did not differ as a function of sex. In (A): *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001 compared to session 1. In (C): *p<0.05, **p<0.01 comparing active to inactive lever pressing. In (D): *p<0.05 comparing the slopes of male and female heroin intake fitted curves.