Abstract
BackgroundDopaminergic functioning is thought to play critical roles in both motivation and addiction. There is preliminary evidence that dopamine agonists reduce the motivation for cigarettes in smokers. However, the effects of pramipexole, a dopamine D3 receptor preferring agonist, have not been investigated.The aim of this study was to examine the effects of an acute dose of pramipexole on the motivation to earn cigarettes and nondrug rewards.MethodsTwenty dependent and 20 occasional smokers received 0.5 mg pramipexole using a double-blind, placebo-controlled crossover design. Motivation for cigarettes and consummatory nondrug rewards was measured using the DReaM-Choice task, in which participants earned, and later “consumed,” cigarettes, music, and chocolate. Demand for cigarettes was measured using the Cigarette Purchase Task (CPT). Self-reported craving, withdrawal, and drug effects were also recorded.ResultsDependent smokers chose (p < .001) and button-pressed for (p < .001) cigarettes more, and chose chocolate less (p < .001), than occasional smokers. Pramipexole did not affect the number of choices for or amount of button-pressing for any reward including cigarettes, which was supported by a Bayesian analysis. The dependent smokers had greater demand for cigarettes than occasional smokers across all CPT outcomes (ps < .021), apart from elasticity. Pramipexole did not affect demand for cigarettes, and this was supported by Bayesian analyses. Pramipexole produced greater subjective “feel drug” and “dislike drug” effects than placebo.ConclusionsDependent and occasional cigarette smokers differed in their motivation for cigarettes but not for the nondrug rewards. Pramipexole did not acutely alter motivation for cigarettes. These findings question the role of dopamine D3 receptors in cigarette-seeking behavior in dependent and occasional smokers.ImplicationsThis study adds to the growing literature about cigarette versus nondrug reward processing in nicotine dependence and the role of dopamine in cigarette-seeking behavior. Our results suggest nicotine dependence is associated with a hypersensitivity to cigarette rewards but not a hyposensitivity to nondrug rewards. Furthermore, our results question the importance of dopamine D3 receptors in motivational processing of cigarettes in occasional and dependent smokers.
Highlights
Mesocorticolimbic dopamine functioning putatively plays a critical role in the reinforcing effects of recreational drugs, including nicotine,[1] and the motivation for and learning about nondrug rewards.[2,3,4] Over the past few decades, drug addiction has come to be conceptualized as a condition stemming from perturbations in the dopamine system.[5,6,7] More recently, theories of addiction have emphasized the apparent concomitant increase in sensitivity to drug reward and decrease in sensitivity to nondrug reward.[8]
Pramipexole did not affect the number of choices for or amount of button-pressing for any reward including cigarettes, which was supported by a Bayesian analysis.The dependent smokers had greater demand for cigarettes than occasional smokers across all Cigarette Purchase Task (CPT) outcomes, apart from elasticity
There was no evidence that the groups differed on any nonsmoking demographic variables apart from Beck Depression Inventory (BDI), on which dependent smokers (10.80, SD = 7.50) had a greater score than occasional smokers
Summary
Mesocorticolimbic dopamine functioning putatively plays a critical role in the reinforcing effects of recreational drugs, including nicotine,[1] and the motivation for and learning about nondrug rewards.[2,3,4] Over the past few decades, drug addiction has come to be conceptualized as a condition stemming from perturbations in the dopamine system.[5,6,7] More recently, theories of addiction have emphasized the apparent concomitant increase in sensitivity to drug reward and decrease in sensitivity to nondrug reward.[8]. The aim of this study was to examine the effects of an acute dose of pramipexole on the motivation to earn cigarettes and nondrug rewards. Pramipexole did not affect the number of choices for or amount of button-pressing for any reward including cigarettes, which was supported by a Bayesian analysis.The dependent smokers had greater demand for cigarettes than occasional smokers across all CPT outcomes (ps < .021), apart from elasticity. Conclusions: Dependent and occasional cigarette smokers differed in their motivation for cigarettes but not for the nondrug rewards. Pramipexole did not acutely alter motivation for cigarettes These findings question the role of dopamine D3 receptors in cigarette-seeking behavior in dependent and occasional smokers. Implications: This study adds to the growing literature about cigarette versus nondrug reward processing in nicotine dependence and the role of dopamine in cigarette-seeking behavior.
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