, 2008; see also Hughes, Rose, & Callas, 2000). Therefore, caution should be exercised in generalizing the findings of this study to smokers without histories of alcohol dependence. Third, we did not examine the relationship between plasma bupropion levels and the reinforcing efficacy and subjective effects of selleck chemical U0126 smoking. Individual differences in these levels may have affected responses on our dependent measures. In addition, the reinforcing efficacy and subjective effects of the study medication on smoking were determined only 2 days after participants had begun taking the 300 mg dose of bupropion. Findings by Hawk et al. (2008), discussed above, suggest that longer medication treatment may produce more pronounced effects. Fourth, participants in our study were not smoking deprived during study assessments.

It is possible that the effects of bupropion on study measures would be more pronounced under conditions of nicotine deprivation and withdrawal. Finally, cigarette deprivation was controlled by having participants smoke before completing the purchase task. Future research might examine the effects of bupropion under conditions of progressive cigarette deprivation (e.g., Hitsman et al., 2008). Longer duration of deprivation might be expected to render demand for cigarettes less elastic (c.f., Field, Santarcangelo, Sumnall, Goudie, & Cole, 2006; Giordano et al., 2002), and from this baseline, any effects of bupropion on elasticity (i.e., �� values) may be more easily detected.

In conclusion, behavioral economic methods have been used extensively in animals and humans to study the reinforcing efficacy of drugs of abuse, including nicotine, and can be readily applied in human studies to investigate the effects of pharmacotherapies on nicotine reinforcement (Hursh & Silberberg, 2008). The present study suggests that bupropion has no detectable effect on demand for cigarettes. However, changes in elasticity from the first to the second week of participation were predictive of subsequent success in smoking cessation. Future laboratory studies might profitably use behavioral economic measures to investigate the effects of other medications on nicotine reinforcement, including studies in which the effects of two or more medications are compared. Behavioral economic approaches can also be used in clinical trials to investigate the relation between the effect of a medication on nicotine reinforcement and smoking cessation outcome. Future studies might also consider investigating the effects of medication on nicotine reinforcement during stress induction. Funding This research Entinostat was supported by research grants (RO1 DA 017370 and R21 DA 023564) from the National Institute on Drug Abuse. Declaration of Interests None declared.