Dopamine (DA) is a chemical signal in the brain linked to learning, memory, and habits.
Stimulant drugs like methylphenidate can increase DA in the brain. Researchers want to
measure DA with and without this drug. They want to learn how methylphenidate and brain
dopamine affect body responses, mood, and thinking.
To better understand the role of dopamine in the brain and the effects of methylphenidate.
Adults ages 18-55 who have used alcohol or stimulant drugs but have no drug dependence.
Participants will be screened with:
Question about medical, psychiatric, and alcohol and drug use history
Questions to see if it s safe to have a PET/MRI scan
Blood and urine tests
Breath test for alcohol
Participants will have 3 or 4 study visits. At each visit they will have:
Urine and breath tested for alcohol and drugs
A thin plastic tube (catheter) inserted in each arm by needle
A small amount of radioactive chemical injected through the catheter.
PET/MRI scan. Participants will lie still on a table that slides in and out of a metal
cylinder surrounded by a strong magnetic field. Their vital signs will be monitored.
They will get earmuffs for loud noises. Before the scan, participants will get the study
drug or placebo through the catheter. They may also get a sugar pill (placebo). They
will get a small meal and have blood drawn.
Tests of memory, attention, and thinking.
Participants will wear an activity monitor on the wrist for one week.
Objectives: The overarching goal of this study is to assess the dynamic association
between dopamine (DA) D2 receptor (D2R) occupancymeasured by positron emission
tomography (PET) with [11C]raclopride and brain activity inferred by pharmacological
magnetic resonance imaging (phMRI) in the human brain, and to assess the relative
sensitivity and specificity of the neurovascular coupling for slow (oral) versus rapid
(intravenous, IV) stimulant methylphenidate (MP) delivery. Secondary objectives are to
assess the associations between behavioral measures (heart and respiration rates and
blood pressure, motor and sleep parameters, and neuropsychological testing variables),
D2R occupancy and fMRI signals.
Study population: 10 healthy males and 10 healthy females 18-55 years old will be
Design: Double-blind. Participants will undergo simultaneous PET/phMRI, to evaluate
dynamic changes in D2R occupancy by DA with [11C]raclopride and in bloodoxygenationlevel
dependent (BOLD) signals, under MP or placebo (PL). The participants will be
scanned on 3 different occasions: 1) oral-MP (60 mg) and iv PL (3 cc saline), 2) oral-PL
and iv-MP (0.25 mg/kg in 3 cc sterile water) and 3) oral PL and iv PL, which will be
carried in different study days with at least 48 hours between them and their order will
be randomized across subjects. Participants and researchers will be blind to the nature
of the stimulant drug (MP/PL).
Outcome parameters: The scale factor between the distribution volume ratio (DVR) and the
BOLD signal in the dorsal and ventral striatum for the slow and fast MP challenges.
Oral Methylphenidate followed by IV placebo,
Oral placebo followed by IV Methylphenidate,
Oral Placebo followed by IV Placebo
Clinical Study Identifier
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.
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