Locomotor response to novelty predicts a rat's propensity to self-administer nicotine

Rationale: A positive correlation between responding to novelty and propens ity to subsequently self-administer a drug has been reported for opioids an d psychomotor stimulants but remains to be investigated for nicotine. Objec tive: The possibility that locomotor responding to novelty can predict a ra t's propensity to self-administer nicotine was therefore assessed. Methods: Rats' locomotor response to a novel environment was assessed, and animals were subsequently tested for their self-administration of nicotine. Results : Significant positive correlations were obtained between responding to nov elty and acquisition of nicotine self-administration over 12 days of testin g under fixed-ratio schedules as well as subsequent responding for the drug under a progressive-ratio (PR) schedule of reinforcement. When designated as high (HR) or low (LR) responders based on whether their locomotor respon ses on the novelty screen were above or below the median activity level of the subject sample, HR animals, compared with LR rats, acquired nicotine se lf-administration more readily and worked more to obtain the drug when test ed under the PR schedule. Conclusion: These findings are consistent with th ose obtained with other drugs and suggest that locomotor responding to a no vel environment can be used to predict a rat's propensity to self-administe r nicotine.