Mean (±SEM) relative expression of Oprm1 mRNA in the PVN of adult F1 males (panel A), adult F2 males (panel B), and adult F1 females (panel C) as measure 30 minutes after morphine administration. F1 males: main effect of dose (F[2,35]=7.5; p<0.01). F2 males: main effect of grandmaternal adolescent exposure (F[1,40]=5.71; p<0.05), significant interaction (F[2,40]=6.12; p<0.01). *** p<0.0001 as compared to SAL-F2 males at same dose. F1 females: Main effect of maternal adolescent exposure (F[1,31]=9.07; p<0.01) All N’s = 6–8 per group.