7-Nitroindazole blocks nicotine-induced conditioned place preference but not LiCl-induced conditioned place aversion

We have shown previously that the neuronal nitric oxide synthase (nNOS) is involved in the rewarding effect of cocaine as determined by the conditione d place preference (CPP) paradigm, in the present. study we investigated th e effect of the nNOS inhibitor 7-nitroindazole (7-NI) on nicotine-induced C PP and LiCl-induced conditioned place aversion (CPA) in Swiss Webster mice. Mice treated with nicotine (0.5 mg/kg) or saline every other day for 8 day s (four drug and four saline sessions) developed CPP that was completely bl ocked by pretreatment with 7-NI (25 mg/kg). Mice treated with LiCl (150 mg/ kg) developed marked aversion to the LiCl-paired compartment. LiCl-induced CPA was not affected by the pretreatment with 7-NI. These findings suggest that nitric oxide (NO) plays a role in the acquisition of reward but not of aversion and that the blockade of nicotine-induced CPP is probably nor due to impairment of learning and memory. NeuroReport 11:947-949 (C) 2000 Lipp incott Williams & Wilkins.