Recently Abstinent Smokers Exhibit Mood-Associated Dopamine Dysfunction in the Ventral Striatum Compared to Nonsmokers: A [11C]-(+)-PHNO PET Study. Issue 5 (10th October 2021)

• Record Type: Journal Article
• Authors: Calakos, Katina C; Hillmer, Ansel T; Angarita, Gustavo A; Baldassarri, Stephen R; Najafzadeh, Soheila; Emery, Paul R; Matuskey, David; Huang, Yiyun; Cosgrove, Kelly P
• Is Part Of: Nicotine & tobacco research. Volume 24:Issue 5(2022)
• Page Start: 745
• Page End: 752
• Publication Date: 2021-10-10
• Subjects: Nicotine -- Periodicals; Tobacco -- Research -- Periodicals; Tobacco habit -- Periodicals; Nicotine -- Periodicals; Tobacco -- Periodicals; Smoking -- Periodicals; 613.85
• DOI: 10.1093/ntr/ntab208
• Languages: English
• ISSNs: 1462-2203

Abstract

Abstract: Introduction: Chronic nicotine exposure desensitizes dopamine responses in animals, but it is not known if this occurs in human tobacco smokers. Deficits in dopamine function are likely to make smoking cessation difficult. We used positron emission tomography (PET) brain imaging with the dopamine D2/3 receptor agonist radioligand [ 11 C]-(+)-PHNO to determine if abstinent smokers exhibit less amphetamine-induced dopamine release in the ventral striatum than nonsmokers, and whether this was associated with clinical correlates of smoking cessation. Methods: Baseline [ 11 C]-(+)-PHNO scans were acquired from smokers ( n = 22, 7 female, abstinent 11 ± 9 days) and nonsmokers ( n = 20, 7 female). A subset of thirty-seven participants (18 smokers) received oral amphetamine (0.5 mg/kg) three hours before a second [ 11 C]-(+)-PHNO scan. Binding potential ( BP ND ) (i.e., D2/3 receptor availability) was estimated at baseline and postamphetamine in the ventral striatum. Amphetamine-induced percent change in BP ND was calculated to reflect dopamine release. Subjects also completed the Center for Epidemiologic Studies Depression Scale (CES-D). Results: There were no group differences in baseline BP ND . Amphetamine-induced percent change in BP ND in the ventral striatum was significantly lower in abstinent smokers compared to nonsmokers ( p =0.019; d= 0.82). Higher CES-D scores were significantly associated with lower ventral striatal percent change in BP ND for abstinent smokers ( r s =-0.627, p =0.025). Conclusions: In conclusion, abstinent smokers exhibited significantly less amphetamine-induced dopamine release in the ventral striatum than nonsmokers. In abstinent smokers, worse mood was significantly associated with less striatal dopamine release. Our findings highlight a potential neural mechanism that may underlie negative mood symptoms during early abstinence. Implications: This study combined quantitative PET imaging and an amphetamine challenge to examine striatal dopamine function during early smoking cessation attempts. The findings demonstrate that recently abstinent tobacco smokers exhibit significant, mood-associated striatal dopamine dysfunction compared to nonsmokers. This study advances our knowledge of the neurobiology underlying early quit attempts, and bridges novel neural findings with clinically relevant symptoms of smoking cessation. These results may explain the challenge of maintaining long-term abstinence from smoking, and can lend insight into the development of treatment strategies for smoking cessation.