Gene expression of the α-containing nAChR subunits (α2, α3, α4, α5, and α7) in female (naïve control n=6; nicotine treated n=8 and nicotine withdrawal n=8) and male (naïve control n=8; nicotine treated n=8 and nicotine withdrawal n=6) rats in Study 2. The data are expressed as a fold change relative to naïve controls (± SEM). Asterisks (*) denote a difference from naïve controls, number signs (#) denote a difference from nicotine-treated rats that received saline, and daggers (†) denote a sex difference in their respective treatment condition (p ≤ 0.05).