Figure 2.
Active lever responding for saccharin and nicotine reinforcement in the PR testing procedure. Bars depict mean ± SEMs for 3-day averages of active lever presses for each saline/nicotine exposure condition. #, p<0.05 main effect of adolescent nicotine. Post hoc tests for adolescent nicotine × adult nicotine × reinforcement interactions: **, p<0.01 sacch reinforcement vs nic reinforcement (within subjects) comparisons for nic/sal and nic/nic; ‡, p<0.05 nic/sal vs sal/sal, sal/nic and nic/nic (sacch reinforcement; between subjects); +, p<0.05 sal/sal vs nic/nic (nic reinforcement; between subjects). sal/sal: adolescent saline-exposed mice re-exposed to saline in adulthood; sal/nic: adolescent saline-exposed mice re-exposed to nicotine in adulthood; nic/sal: adolescent nicotine-exposed mice re-exposed to saline in adulthood; nic/nic: adolescent nicotine-exposed mice re-exposed to nicotine in adulthood; sacch: saccharin; nic: nicotine.