Preliminary evidence from planarians that cotinine establishes a conditioned place preference.

• The metabolites of nicotine have not been studied adequately, with cotinine being the primary nicotine metabolite. • Planarians have been used to study the effects of nicotine and were used in the present study to investigate cotinine's effects. • Place learning or conditioned place preference is used to study the effects of drugs such as nicotine. • Nicotine will establish place learning and our data demonstrate for the first time that cotinine will establish place learning with planarians. • Our data suggest that cotinine may be contributing to nicotine's effects. While the psychoactive stimulant nicotine has been the subject of extensive research, considerably less attention has focused on other compounds found in either tobacco smoke or that are nicotine metabolites. Recent papers have suggested that some of the compounds in question may either alter nicotine's effects or have reinforcing properties themselves, although they would only be experienced after consumption of tobacco. The potential for these compounds to function as reinforcers or to potentiate the reinforcing properties of nicotine merits investigation. To pursue this line of inquiry, we examined cotinine in a planarian model of environmental place preference. In the present study, planarians demonstrated that the compound cotinine, which is present in tobacco smoke, and is also the principal nicotine metabolite, establishes a conditioned place preference. These data represent the first ever demonstration that cotinine will establish a conditioned place preference in planarians and possibly contribute to the addictive properties of nicotine. [ABSTRACT FROM AUTHOR]