Fig 1: Nicotine consumption suppresses estrogen-induced increases in estrogen receptor alpha (ERa) mRNA in the nucleus accumbens core (NAcore) and ventral tegmental area (VTA) in ovariectomized (OVX) Females. A, Immunocytochemistry reveals ERa (red) and estrogen receptor beta (ERß) (purple) on somas (blue) in the NAcore (AC = anterior commissure, delineated by which dotted line). B, RT-qPCR revealed a amin effect of group on Esr1 (ERa) mRNA in the NAcore whereas nicotine naive estrone (E1)+estrogen (E2)-treated rats had higher levels compared with all other groups (*p < 0.05; mean ± SEM). ERa mRNA was also found to be higher in the nicotine naive E2-treated group compared with the nicotine naive vehicle (VEH) group (*p < 0.05, mean ± SEM). C, There was no main effect of group on Esr2 (ERß) in the NAcore between groups (LME; p > 0.05; mean ± SEM). D, Immunocytochemistry reveals ERa (red) and ERß (purple) on dopaminergic somas (green) in the VTA. E, RT-qPCR revealed a main effect of group on ERa mRNA in the VTA. Nicotine naive females treated with E2 had higher mRNA compared with nicotine-naive vehicle, nicotine-experienced vehicle, nicotine-experienced E2, and nicotine-experienced E1+E2 (*p < 0.05; mean ± SEM). F, RT-qPCR revealed a main effect of group on ERß mRNA. Nicotine-experienced vehicle had more mRNA compared with nicotine naive E1+E2-treated animals (*p < 0.05; mean ± SEM).Figure Contributions: Erin E. Maher collected the confocal micrographs. Erin E. Maher and Zachary A. Kipp performed RNA extraction and RT-qPCR experiments. Erin E. Maher analyzed the data.