NIH Clinical Research Studies

Protocol Number: 07-AA-0026

Active Accrual, Protocols Recruiting New Patients

OPRM1 A118G SNP, Alcohol Response, and Striatal Dopamine
This study will examine the relationship between variations in a gene called OPRM1 and the response to alcohol. The OPRM1 (Mu-opioid Receptor-1) gene helps regulate brain pathways involved in experiencing pleasure. Brain pathways use a chemical called dopamine. Different forms of the OPRM1 gene may lead to differences in how dopamine is released and subsequently to differences in a person's response to alcohol.

Healthy non-smokers between 21 and 45 years of age may be eligible for this study. Candidates are screened with a medical and psychiatric history and physical examination, blood and urine tests, and breathalyzer (breath alcohol test). A blood test is also done to determine the variant of OPRM1 gene.

Participants undergo the following procedures in three study sessions:

Session 1

" Breathalyzer test, urine test for illicit drugs and pregnancy test for women who can become pregnant.

" Insertion of catheters (plastic tubes) into a vein in one arm for infusing alcohol and into the other arm for drawing blood samples.

" Completion of questionnaires on how intoxicated the subject feels.

" Blood draw for research studies.

" Eye movement test (a visor with a digital camera tracks the subject's eye movements while he or she watches lights on a computer screen).

" 45-minute alcohol infusion (up to 0,08 grams per deciliter - a level considered in most states as driving under the influence of alcohol).

" Repeat breathalyzer, questionnaires, eye movement test and blood draw every 15 minutes during the infusion and again after the infusion is complete.

" Subjects remain in the clinic until their blood alcohol content falls below 0.02 g/dL, determined by a breathalyzer test done every 15 minutes. Subjects can usually return home about 3 to 4 hours after the alcohol infusion stops.

Sessions 2 and 3

The procedure is the same as for session 1, except subjects receive an infusion of alcohol one session and an infusion of saline (salt water) the other. Also, subjects undergo positron emission tomography (PET) scanning during the infusions. For this test, the subject lies on a bed that slides in and out of a doughnut-shaped scanner. A custom-molded mask is used to support the head and prevent it from moving during the scanning. A small amount of radioactive substance called C-11 raclopride is injected through one of the catheters to trace brain dopamine activity.

Sponsoring Institute:
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Recruitment Detail
Type: Participants currently recruited/enrolled
Gender: Male & Female
Referral Letter Required: No
Population Exclusion(s): Children

Eligibility Criteria:

1. Male and female participants between 21-45 years of age.

2. Good health as determined by medical history, physical exam, EKG and lab tests.

3. Current non-smokers, defined as smoking less than 10 cigarettes per week. Participants who quit smoking for over 1 year can be included.

4. Females will have normal menstrual cycles and will be tested during the follicular phase of their cycle (within 15 days of offset of menses) and must have a negative urine pregnancy (hCG) test at the start of each study session.

5. An equal number of final participants will be of OPRM1 118 A/A vs. 118A/G or 118G/G genotype.


1. Current or prior history of any significant disease, including cardiovascular, respiratory, gastrointestinal, hepatic, renal, endocrine, or reproductive disorders, or a positive hepatitis or HIV test at screening.

2. Current Axis-I psychiatric illness.

3. Current or prior history of any alcohol or drug dependence, as well as non-drinkers (alcohol-naive individuals or current abstainers).

4. Positive result on urine screen for illicit drugs.

5. Nursing, pregnancy or intention to become pregnant for women. Female participants will undergo a clinical interview and a urine beta-hCG test to ensure they are not pregnant. If it is not possible to document non-pregnancy, the study will not be performed.

6. Inability to undergo an MRI scan of the brain due to claustrophobia or anxiety when confined to small spaces such as the magnet bore, or due to the presence of metallic implants.

7. Use of prescription or OTC medications known to interact with alcohol within 2 weeks of the study. These include, but may not be limited to: isosorbide, nitroglycerine, benzodiazepines, warfarin, anti-depressants such as amitriptyline, clomipramine and nefazodone, anti-diabetes medications such as glyburide, metformin and tolbutamide, H2-antagonists for heartburn such as cimetidine and ranitidine, muscle relaxants, anti-epileptics including phenytoin and phenobarbital codeine, and narcotics including darvocet, percocet and hydrocodone. Drugs known to inhibit or induce enzymes that metabolize alcohol should not be used for 4 weeks prior to the study. These include chlorzoxazone, isoniazid, metronidazole and disulfiram. Cough-and-cold preparations which contain anti-histamines, pain medicines and anti-inflammatories such as aspirin, ibuprofen, acetaminophen, celecoxib and naproxen, should be withheld for at least 72 hours prior to each study session.

8. Self-reported history of flushing upon intake of alcohol.

Special Instructions:
Currently Not Provided
C-11 Raclopride
Recruitment Keyword(s):
Healthy Volunteer
Investigational Drug(s):
C-11 Raclopride
O-15 H2O
Investigational Device(s):
Supporting Site:
National Institute on Alcohol Abuse and Alcoholism

Patient Recruitment and Public Liaison Office
Building 61
10 Cloister Court
Bethesda, Maryland 20892-4754
Toll Free: 1-800-411-1222
TTY: 301-594-9774 (local),1-866-411-1010 (toll free)
Fax: 301-480-9793


Kreek MJ, LaForge KS, Butelman E. Pharmacotherapy of addictions. Nat Rev Drug Discov. 2002 Sep;1(9):710-26.

Contet C, Kieffer BL, Befort K. Mu opioid receptor: a gateway to drug addiction. Curr Opin Neurobiol. 2004 Jun;14(3):370-8.

Roberts AJ, McDonald JS, Heyser CJ, Kieffer BL, Matthes HW, Koob GF, Gold LH. mu-Opioid receptor knockout mice do not self-administer alcohol. J Pharmacol Exp Ther. 2000 Jun;293(3):1002-8.

Active Accrual, Protocols Recruiting New Patients

If you have:

Command Menu Bar

Search The Studies | Help | Questions |
Clinical Center Home | NIH Home

Clinical Center LogoNational Institutes of Health Clinical Center Bethesda, Maryland 20892. Last update: 09/17/2008
Search The Studies Help Questions