Behavioral Psychopharmacology Research Laboratory, McLean Hospital, Belmont MA, USA.
Pharmacol Biochem Behav. 2013 Feb;103(4):710-6. doi: 10.1016/j.pbb.2012.11.012. Epub 2012 Dec 3.
Despite the well-known adverse health consequences of smoking, approximately 20% of US adults smoke tobacco cigarettes. Much of the research on smoking reinforcement and the maintenance of tobacco smoking behavior has focused on nicotine; however, a number of other non-nicotine factors are likely to influence the reinforcing effects of smoked tobacco. A growing number of studies suggest that non-nicotine factors, through many pairings with nicotine, are partially responsible for the reinforcing effect of smoking. Additionally, both clinical studies and preclinical advances in our understanding of nicotinic receptor regulation suggest that abstinence from smoking may influence smoking reinforcement. These experiments were conducted for 2 reasons: to validate a MRI-compatible cigarette smoking device; and to simultaneously investigate the impact of nicotine, smoking-associated conditioned reinforcers, and smoking abstinence state on subjective ratings of smoking reinforcement. Participants smoked nicotine and placebo cigarettes through an fMRI compatible device in an overnight-abstinent state or in a nonabstinent state, after having smoked a cigarette 25minutes prior. Outcome measures were within-subject changes in physiology and subjective ratings of craving and drug effect during the smoking of nicotine or placebo cigarettes on different days in both abstinence states. Cigarette type (nicotine vs. placebo) had a significant effect on positive subjective ratings of smoking reinforcement ("High", "Like Drug", "Feel Drug"; nicotine>placebo). In contrast, abstinence state was found to have significant effects on both positive and negative ratings of smoking reinforcement ("Crave", "Anxiety", "Irritability"; abstinence>nonabstinence). Interaction effects between abstinence and nicotine provide clues about the importance of neuroadaptive mechanisms operating in dependence, as well as the impact of conditioned reinforcement on subjective ratings of smoking-induced high.
尽管众所周知吸烟对健康有不良影响，但仍有约 20%的美国成年人吸烟。大多数关于吸烟强化和维持吸烟行为的研究都集中在尼古丁上；然而，许多其他非尼古丁因素可能会影响吸烟的强化作用。越来越多的研究表明，非尼古丁因素通过与尼古丁的多次配对，部分解释了吸烟的强化作用。此外，临床研究和我们对烟碱型乙酰胆碱受体调节的临床前进展都表明，戒烟可能会影响吸烟的强化作用。进行这些实验有两个原因：一是验证一种与 MRI 兼容的吸烟装置；二是同时研究尼古丁、与吸烟相关的条件性强化物以及戒烟状态对吸烟强化的主观评价的影响。在一个夜间戒烟状态或非戒烟状态下，参与者通过一个与 fMRI 兼容的设备吸烟，吸烟前 25 分钟吸一支烟。在不同的戒烟状态下，在不同的日子里，通过生理和对吸烟时的渴望和药物作用的主观评价的个体内变化来衡量结果。香烟类型（尼古丁与安慰剂）对吸烟强化的积极主观评价有显著影响（“高”、“像药物”、“感觉药物”；尼古丁>安慰剂）。相比之下，戒烟状态对吸烟强化的积极和消极评价都有显著影响（“渴望”、“焦虑”、“烦躁”；戒烟>非戒烟）。戒烟和尼古丁之间的相互作用效应提供了有关依赖中神经适应机制的重要性以及条件强化对吸烟引起的兴奋的主观评价的影响的线索。
