[Rewarding property of nicotine and methamphetamine tested by conditioned place preference in rats: effect of chronic nicotine pretreatment].

Nicotine is classified as a dependence-producing drug. This study investigated the rewarding property of nicotine employing the conditioned place preference (CPP) paradigm in a three-compartment box, and compared it with that of methamphetamine (MAP). In place conditioning using a biased method, rats were placed in one (white or black) compartment under the drug treatment and placed in the other compartment without drug. In the preference test conducted after conditioning, the time spent in the nicotine-paired compartment significantly increased compared with that in the baseline test, suggesting nicotine's rewarding property, although the property was weaker compared with that of MAP. Chronic nicotine pretreatment by a subcutaneous osmotic mini-pump for 7days before place conditioning tended to increase the rewarding property of nicotine, and the possible mechanism of this effect was discussed.