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| Sponsored by: |
National Institute of Mental Health (NIMH) |
|---|---|
| Information provided by: | National Institutes of Health Clinical Center (CC) |
| ClinicalTrials.gov Identifier: | NCT00062946 |
Purpose
The purpose of this study is to measure molecules on or in cells that interact with a chemical in the nervous system, called dopamine. Investigators will obtain two kinds of images of the brain-a position emission tomography (PET) scan and a magnetic resonance imaging (MRI) scan.
Thirty-eight participants aged 18 to 45 will be enrolled in this study. They must have no history of medical or psychiatric illness, including substance abuse. Participants will have four appointments at NIH. On the first visit, they will undergo a physical exam, a medical history, and lab tests. The second and third visits will involve PET scans and the fourth visit will involve an MRI scan.
Participants will be compensated up to $430 for their involvement in this study.
| Condition | Intervention | Phase |
|---|---|---|
|
Healthy |
Drug: (18F)fallypride |
Phase II |
| Study Type: | Interventional |
| Study Design: | Treatment |
| Official Title: | PET Imaging of Dopamine D2 Receptors and Extracellular Dopamine With (18F)Fallypride, D-Amphetamine, and Alpha-Methyl-Para-Tyrosine in Healthy Subjects |
| Estimated Enrollment: | 45 |
| Study Start Date: | June 2003 |
| Estimated Study Completion Date: | August 2007 |
Abnormalities of dopaminergic function have been implicated in a number of neurological and psychiatric illnesses, including Parkinson's disease, schizophrenia, and psychostimulant dependence syndromes. Functional imaging with positron emission tomography (PET) and single photon emission computed tomography (SPECT) have demonstrated the feasibility of in vivo measurement of the distribution and the density of dopamine (DA) D1 and D2 receptors in humans. Besides simple measurement of receptor density, it has been shown that the competition between endogenous neurotransmitters and radiolabeled tracers might provide a tool to estimate extracellular levels of neurotransmitters. However, most of those studies have been confined to the striatum. In this protocol using a PET tracer (18F)fallypride, we will estimate both stimulant-induced DA release and baseline DA levels in the striatum and extrastriatal regions by comparing baseline scans and those after d-amphetamine or alpha-methyl-para-tryosine (AMPT) adminstration. In addition, to explore genetic factors that determine synaptic DA levels, allelic variations of two genes that regulate DA levels, catechol-O-methyltransferase and dopamine transporter, will be studied.
A recent study showed that oral administration of d-amphetamine induced displacement of (11C) raclopride in a similar way as the commonly used method of i.v. administration. The current protocol will be performed in two steps. First, the method of d-amphetamine administration will be determined by studying effects of oral d-amphetamine on the binding of (18F) fallypride binding. If oral administration effectively displaces the radioligand binding, this method will be applied in the subsequent study of examining effects of each of d-amphetamine and AMPT in individual subjects.
If this study successfully detects the influence of DA levels on (18F)fallypride binding, the same design will be applied to the studies of patients with psychiatric and neurological disorders.
Eligibility| Ages Eligible for Study: | 18 Years to 45 Years |
| Genders Eligible for Study: | Both |
| Accepts Healthy Volunteers: | Yes |
Age 18-45, inclusive
In good general health on basis of history and physical examination
Normal screening laboratory studies including thyroid function tests, blood count, serum electrolytes, liver and kidney function, and urinalysis
Normal ECG at a resting condition
Normal blood pressure
No illegal drug use based on urine drug screen
EXCLUSION CRITERIA:
Pregnancy/Nursing
Evidence of active mental or neurological illness
Medically significant biochemical or hematological abnormality on screening laboratory studies
Abnormal ECG
High Blood Pressure (above 140 systolic and/or above 90 dystolic pressure)
History of myocardial infarction or angina pectoris
Positive urine drug screen or use of alcohol within one week prior to each PET study
History of substance abuse or dependence within 6 months
Presence of ferromagnetic metal in the body or heart pacemaker
Body weight more than 93 kg to limit AMPT dose to 4 g/ day (only for subjects having four PET scans and d-amphetamine and AMPT administration)
Claustrophobia
Contacts and Locations More Information
| Study ID Numbers: | 030104, 03-M-0104 |
| Study First Received: | June 17, 2003 |
| Last Updated: | August 16, 2007 |
| ClinicalTrials.gov Identifier: | NCT00062946 History of Changes |
| Health Authority: | United States: Federal Government |
|
Thalamus Cerebral Cortices Quantification Reproducibility Dopamine Release (18F) Fallypride |
D-Amphetamine Alpha-Methyl-Para-Tyrosine (AMPT) PET Dopamine D2 Receptor Healthy Volunteer HV |
|
Dopamine Uptake Inhibitors Neurotransmitter Agents Tyrosine Central Nervous System Stimulants Healthy Cardiovascular Agents Methamphetamine |
Dopamine Dextroamphetamine Alpha-Methyltyrosine Dopamine Agents Amphetamine Peripheral Nervous System Agents |
|
Dopamine Uptake Inhibitors Neurotransmitter Agents Neurotransmitter Uptake Inhibitors Molecular Mechanisms of Pharmacological Action Sympathomimetics Cardiotonic Agents Physiological Effects of Drugs Enzyme Inhibitors Central Nervous System Stimulants Cardiovascular Agents |
Protective Agents Pharmacologic Actions Dopamine Autonomic Agents Dextroamphetamine Therapeutic Uses Alpha-Methyltyrosine Dopamine Agents Peripheral Nervous System Agents Central Nervous System Agents |
