Effects of Nicotine on Brain Opioid Receptors

Exclusion Criteria

• •Current enrollment or plans to enroll in a smoking cessation program, or use other smoking cessation medications in the next 2 months
• •Provide a Carbon Monoxide reading of ≤10 ppm at Medical screening.
• •History of substance abuse and/or currently receiving treatment for substance abuse (e.g., alcohol, opioids, cocaine, marijuana, or stimulants)
• •Current alcohol consumption that exceeds 25 standard drinks/week
• •Providing a breath alcohol concentration (BAC) reading of \> 0.01 at any session.
• •Women who are pregnant, planning a pregnancy, or lactating; all female subjects shall undergo a urine pregnancy test at each session
• •Women of child-bearing age must agree in writing to use an approved method of contraception
• •History or current diagnosis of psychosis, major current depression or bipolar disorder, ADHD, schizophrenia, or any Axis 1 disorder as identified by the MINI
• •Serious or unstable disease within the past 6 months (e.g., cancer \[except melanoma\], heart disease, HIV)
• •History of epilepsy or a seizure disorder
• •History or current diagnosis (last 6-months) of abnormal rhythms and/or tachycardia (\>100 beats/minute); history or current diagnosis of COPD, cardiovascular disease (stroke, angina, coronary heart disease), heart attack in the last 6 months, uncontrolled hypertension (SBP\>150 or DBP\>90)
• •Any medical or neurological condition that might interfere with the distribution of the radiotracer as determined by the study MD
• •Current or past use (within past 12 months) of any medications containing naltrexone or other MOR antagonists (e.g., Revia, Trexan)
• •Current use or recent discontinuation (within last 14-days) of the following medications
• •Any form of smoking cessation medication (Zyban, Wellbutrin, Wellbutrin SR, Chantix, NRT)
• •Recent (within last 2 weeks) or planned use of psychotropic medications (anti-psychotics, anti-depressants (tricyclic, SSRI, MAOI), anti-anxiety or panic medications, and stimulants (e.g., Provigil, Ritalin), and opiate-containing medications for chronic pain
• •Allergic response to any form of opioids or naloxone
• •Participants shall be instructed to refrain from using any study prohibited drugs (note - participants are allowed to take prescription medicines not in the exclusion list) throughout their participation in the study.
• •Self-reported history of head trauma or prior seizure, brain (or CNS) tumor
• •Self-reported history of claustrophobia (contraindicated for PET)
• •Inability to complete the baseline study procedures within four hours and/or correctly, as determined by the principal investigator.