A substantial body of evidence implicates the endogenous opioid system, and the mu opioid
receptor (MOR) in particular, in the reinforcing effects of drugs of abuse, including
nicotine. A single nucleotide polymorphism (SNP) in the mu opioid receptor gene (OPRM1 Asp40)
is associated with the ability to quit smoking, as well as nicotine reward and withdrawal
symptoms. However, the precise mechanism through which this SNP influences nicotine
dependence remains unresolved. This positron emission tomography (PET) study will examine
whether this OPRM1 SNP alters MOR binding in response to nicotine in human smokers.
Specifically, we will use [11 C]carfentanil PET imaging to assess the effects of intravenous
(IV) nicotine versus saline (within-subject) on MOR binding potential in 24 chronic smokers
genotyped prospectively and stratified by OPRM1 genotype.