Nicotine serves as a feature-positive modulator of Pavlovian appetitive conditioning in rats

The present experiments examined whether a nicotine state could set the occasion for a pairing between visual cues and a rewarding outcome in rats. Following nicotine administration, presentation of a conditional stimulus (CS; light-on) was followed by brief access to a sucrose solution. When saline was administered, the same CS was presented but was not followed by any consequence. In Experiment 1, two groups assessed whether rats could acquire this Pavlovian feature-positive discrimination via different training procedures. An anticipatory food-seeking conditioned response (CR) developed during the CS on nicotine sessions but not on saline sessions in both groups. In Experiment 2, centrally acting antagonists of nicotinic acetylcholine and opiate receptors (mecamylamine and naloxone, respectively) dose-dependently blocked nicotine's control of the CR, whereas the peripherally acting nicotinic antagonist hexamethonium had no effect. Increasing or decreasing the interval between nicotine administration and testing also attenuated the CR. These results are consistent with the hypothesis that nicotine can occasion appetitive Pavlovian relations via its action at central nervous system cholinergic receptors.