Drugs used in this study included nicotine tartrate (MP Biomedicals, LLC, Solon, OH), RO5263397 (synthesized at Research Triangle Institute, purity > 98%) and mecamylamine hydrochloride (Sigma). nicotine tartrate was dissolved in 0.9% physiological saline, and the pH was adjusted to 7.2–7.4 prior to injection. RO5263397 was dissolved in a mixture of 1 part absolute ethanol, 1 part Emulphor-620 (Rhodia) and 18 parts physiologic saline.36 (link) The dose of RO5263397 (intraperitoneally, i.p.; 5.6 mg/kg) used in these experiments was selected based on our previous findings in which there was no effect on general locomotor activity.30 (link),37 (link) Mecamylamine hydrochloride was dissolved in saline and administered i.p. (1.5 mg/kg).