Effects of Smoking on Opioid Receptor Binding: A PET Study
Status:
Completed
Trial end date:
2015-01-08
Target enrollment:
Participant gender:
Summary
Background:
- Tobacco smoking is one of the most preventable causes of morbidity and mortality in the
world, but the addictive property of nicotine is such that fewer than 10 percent of
people who attempt to quit smoking remain tobacco-free after 1 year. Researchers are
studying the addictive properties of nicotine in an attempt to develop more successful
medication therapies for smoking cessation.
- Nicotine acts on chemical receptors in the brain, including opioid receptors that affect
the perception of pain. Repeated nicotine administration can cause adaptations in the
brain s opioid receptors, which heightens the addictive properties of nicotine and
increases the likelihood and severity of withdrawal symptoms associated with smoking
cessation. Researchers are interested in using positron emission tomography (PET)
scanning to study brain chemical responses to nicotine in current smokers and
nonsmokers.
Objectives:
- To study brain chemical activity related to cigarette smoking and nicotine
administration.
- To compare the brain chemical activity of current daily smokers with that of nonsmokers.
Eligibility:
- Individuals 21 to 50 years of age who are either current smokers (10 to 25 cigarettes daily
for at least 2 years) or have had some exposure to tobacco but have never smoked regularly
(may have had a maximum of 20 cigarettes in their lifetime and none in past year).
Design:
- Eligible participants will undergo initial medical and psychological screening and
neuropsychological testing before beginning the main phase of the study. Participants
will be required to abstain from alcohol and drugs (except caffeine, nicotine, and
prescription drugs) for 24 hours before each session, and smokers will refrain from
smoking after midnight on the night before each session.
- Session 1: Participants will answer questions about nicotine craving and withdrawal
symptoms, followed by a magnetic resonance imaging (MRI) scan to provide baseline
information about brain activity.
- Session 2 and 3: Participants will answer questions about nicotine craving and
withdrawal symptoms, and then will smoke one cigarette (either active nicotine or
placebo). Researchers will document participants consumption of the cigarette. After the
cigarette is smoked, participants will have a PET scan. Blood samples will be drawn
during the PET session.