PET Imaging of Nicotinic Acetylcholine Receptors

Who cannot join

• Psychiatric disease: DSM-IV criteria will be used (DSM-IV, APA, 1994). No subject with a current axis I diagnosis will be allowed. No subject with known claustrophobia will be allowed.
• History of Drug Abuse: Volunteers reporting current or having a significant history of illicit drug abuse (single illicit substance use of more than 10 times in a lifetime for any given substance, except marijuana) will be excluded from the study. Volunteers reporting current use of nicotine will be excluded because nAChRs are usually elevated in smokers, and the purpose of this protocol is to determine the feasibility of measuring nAChRs in vivo. Including smokers at this time may provide results that are more variable and which may overestimate our ability to measure these receptors in nonsmokers. Subjects may use moderate amounts of alcohol and caffeine and smoke an occasional marijuana cigarette. Moderate alcohol use will be defined as less than ten drinks of liquor (1.5 oz) or the equivalent beer (12 oz) or wine (5 oz) per week. Moderate caffeine use will be defined as less than 500 mg of caffeine per day, where 100 mg is equivalent to 1 serving of coffee (5 oz serving), 2.5 servings (12 oz serving) of caffeinated soft drinks, or 2.5 servings of tea (5 oz serving). Occasional marijuana use will be defined as less than or equal to two marijuana cigarettes/month.
• Current Medication Use: Volunteers may not currently use chronic (daily or for more than 10/14 days in the last month) prescription or over the counter medications, (including, but not limited to, anti-hypertensive, anti-allergy, pain). Over the counter or prescription medications may used on an occasional basis (for treatment of self-limited conditions, such as occasional headache, musculoskeletal discomfort, allergic symptoms or pain). All medications will be discontinued at least 5 days before the experimental session.
• CNS disease: History of known structural brain abnormalities (e.g., neoplasm, subarachnoid cysts), cerebrovascular disease, infectious disease (e.g., abscess), history of head trauma (defined as documented loss of consciousness > 5 min or injury requiring hospitalization), history of seizures as an adult, sleep apnea.
• Cardiovascular, pulmonary, or systemic disease: Repeated (measured on three separate occasions) diastolic blood pressure > 90 mm Hg, or systolic blood pressure > 150 mm Hg, known arrhythmia, symptomatic or known coronary artery disease; history of endocarditis, cerebral embolism, obstructive pulmonary disease, asthma, active tuberculosis, known endocrine disease (derangements in adrenal, thyroid, bone or reproductive function) known chronic renal or hepatic dysfunction, known HIV seropositive, known current autoimmune disease involving the CNS, type I diabetes mellitus, current gastrointestinal disease, gastritis or ulcers.
• Special considerations for female subjects. Female participants who are currently pregnant or nursing will not be allowed to participate in this study. Female subjects will be given a serum pregnancy test (quantitative beta HCG) within 24 hours of each PET session.