Effects of R-MOD on nicotine- or nicotine-associated cue-induced reinstatement of nicotine seeking in P-rats. (a, b) Active and inactive lever responses during the last session of nicotine self-administration, last session of extinction, and nicotine-triggered reinstatement testing, illustrating that R-MOD significantly inhibited nicotine priming-induced reinstatement. (c, d) Active and inactive lever responses during the last session of nicotine self-administration and cue-triggered reinstatement testing, illustrating that R-MOD significantly inhibited nicotine-associated cue-induced nicotine-seeking behavior in rats after 3 weeks of withdrawal from the last nicotine self-administration. (e, f) Active and inactive lever responses during the last session of nicotine self-administration, extinction, and reinstatement testing, illustrating that R-MOD (30 or 100 mg/kg) failed to reinstate nicotine-seeking behavior. ###p<0.001, compared with vehicle control.