• INCLUSION CRITERIA FOR SMOKERS:

  1. 21-50 year old males and females
  2. smoke 10 cigarettes per day on average for at least 2 years
  3. urine cotinine level greater than or equal to 200 ng/ml (NicAlert reading greater than or equal to 4)
  4. estimated IQ score greater than or equal to 85 (competent to give informed consent)
  5. medically and psychologically healthy as determined by screening criteria.

EXCLUSION CRITERIA FOR SMOKERS:

1. interest in reducing or quitting tobacco use
2. treatment for nicotine dependence in the past 3 months
3. current drug or alcohol abuse or dependence
4. consumption of more than 15 alcoholic drinks per week during the past month
5. any opiate use in the past 6 months
6. marijuana use greater than one time per week on an average during the past month
7. other drug use greater than 2 time per month on average during the past 3 months.
8. current use of any medication that would interfere with the protocol
9. under the influence of a drug or alcohol at experimental sessions
10. HIV positive
11. history of psychotropic medications
12. history of head injury with unconscious longer than 5 minutes
13. implantable device or foreign body that would make an MRI examination unobtainable
14. MRI abnormality judged clinically significant by the PI
15. use of any investigational medication or device within the previous 30 days
16. donation at least 450 ml of blood or equivalent levels of plasma within the previous 30 days
17. exposure to ionizing radiation that, in combination with the study tracer, would result in a cumulative exposure exceeding 5 rem in one calendar year
18. any subject judged by the PI to be inappropriate for the study.
19. chronic pulmonary disease, including COPD, bronchitis, asthma, and emphysema
20. pregnant, nursing, or become pregnant during the study

INCLUSION CRITERIA FOR NONSMOKERS:

1. 21-50 year old males and females
2. smoked 1-20 cigarettes in their life and none in past year
3. urine cotinine level less than 30 ng/ml (NicAlert reading less than or equal to 1)
4. estimated IQ score greater than or equal to 85 (competent to give informed consent)
5. medically and psychologically healthy as determined by screening criteria.

EXCLUSION CRITERIA FOR NONSMOKERS:

1. use of any tobacco products in the past year
2. current drug or alcohol abuse or dependence
3. consumption of more than 15 alcoholic drinks per week during the past month
4. any opiate use in the past 6 months
5. marijuana use greater than one time per week on average during past month
6. other drug use greater than two times per month on average during past three months.
7. current use of any medication that would interfere with the protocol
8. under the influence of a drug or alcohol at experimental sessions
9. HIV positive
10. history of psychotropic medications
11. history of head injury with unconscious longer than 5 minutes
12. implantable device or foreign body that would make an MRI examination unobtainable
13. MRI abnormality judged clinically significant by the PI
14. use of any investigational medication or device within the previous 30 days
15. donation of at least 450 ml of blood or equivalent levels of plasma within the previous 30 days
16. exposure to ionizing radiation that, in combination with the study tracer, would result in a cumulative exposure exceeding 5 rem in one calendar year
17. any subject judged by the PI to be inappropriate for the study.
18. chronic pulmonary disease, including COPD, bronchitis, asthma, and emphysema
19. pregnant, nursing, or become pregnant during the study