Mu Opioid Receptor Binding Correlates with Nicotine Dependence and Reward in Smokers

• Published in: PloS one Vol. 9; no. 12; p. e113694
• Main Authors: Kuwabara, Hiroto, Heishman, Stephen J., Brasic, James R., Contoreggi, Carlo, Cascella, Nicola, Mackowick, Kristen M., Taylor, Richard, Rousset, Olivier, Willis, William, Huestis, Marilyn A., Concheiro, Marta, Wand, Gary, Wong, Dean F., Volkow, Nora D.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10.12.2014; Public Library of Science (PLoS)
• Subjects: Addictions; Adult; Alcohol; Binding; Biology and Life Sciences; Biomarkers - blood; Brain; Brain - diagnostic imaging; Brain - drug effects; Brain - metabolism; Brain research; Carbon Radioisotopes; Cigarette smoking; Cigarettes; Correlation analysis; Cortex (frontal); Cortex (temporal); Dopamine; Drug abuse; Drug addiction; Drug dependence; Endogenous opioids; Female; Fentanyl - analogs & derivatives; Human subjects; Humans; Male; Medical imaging; Metabolism; Middle Aged; Narcotics; Neuroimaging; Neurosciences; Nicotine; Nicotine - administration & dosage; Nicotine - blood; Nicotinic Agonists - administration & dosage; Nicotinic Agonists - blood; Opioid receptors (type mu); Positron emission; Positron emission tomography; Psychiatry; Psychopharmacology; Radiology; Radiopharmaceuticals; Receptors; Receptors, Opioid, mu - metabolism; Reinforcement; Reward; Science; Self Report; Severity of Illness Index; Smokers; Smoking; Smoking - metabolism; Smoking - psychology; Temporal lobe; Tobacco Use Disorder - diagnostic imaging; Tobacco Use Disorder - metabolism; Tobacco Use Disorder - psychology; Tomography; Young Adult; United States > US; Baltimore Maryland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0113694

The rewarding effects of nicotine are associated with activation of nicotine receptors. However, there is increasing evidence that the endogenous opioid system is involved in nicotine's rewarding effects. We employed PET imaging with [11C]carfentanil to test the hypotheses that acute cigarette smoking increases release of endogenous opioids in the human brain and that smokers have an upregulation of mu opioid receptors (MORs) when compared to nonsmokers. We found no significant changes in binding potential (BPND) of [11C]carfentanil between the placebo and the active cigarette sessions, nor did we observe differences in MOR binding between smokers and nonsmokers. Interestingly, we showed that in smokers MOR availability in bilateral superior temporal cortices during the placebo condition was negatively correlated with scores on the Fagerström Test for Nicotine Dependence (FTND). Also in smokers, smoking-induced decreases in [11C]carfentanil binding in frontal cortical regions were associated with self-reports of cigarette liking and wanting. Although we did not show differences between smokers and nonsmokers, the negative correlation with FTND corroborates the role of MORs in superior temporal cortices in nicotine addiction and provides preliminary evidence of a role of endogenous opioid signaling in frontal cortex in nicotine reward.