Normal PhysiologyNCT00109174
MRS Measurement of Glutamate and GABA Metabolism in Brain
A study testing 3T and 7T device in people with Normal Physiology, run by National Institute of Mental Health (NIMH) at 1 site in United States.
Trial summary
This study will use magnetic resonance spectroscopy (MRS) to measure in the brain the transfer of [13]C as it is naturally metabolized from glucose to specific chemical transmitters. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Normal Physiology
- What is being tested?
- 3T and 7T device
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 200 participants
- Where
- 1 siteUnited States
- Study dates
- 6 Sep 2006to 11 Mar 2030
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 18-65 years of age
- Able to give written informed consent
- Healthy based on medical history and physical exam
- Enrolled in Protocol 01-M-0254 or Protocol 17-M-0181
Who cannot join
- Any current Axis 1 diagnosis
- Clinically significant laboratory abnormalities
- Positive HIV test
- Metallic foreign bodies that would be affected by the magnetic resonance imaging (MRI) magnet, or fear of enclosed spaces likely to make the subject unable to undergo an MRI scan.
- History of neurological illness or injury with the potential to affect study data interpretation, such as multiple sclerosis, Parkinson s disease, seizure disorder or traumatic brain injury
- Prescription psychotropic medication, drug free less than 8 weeks (anticholinergics, benzodiazepine, fluoxetine, antipsychotics, and anticonvulsants)
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- Serious medical illness as determined from H\&P or laboratory testing including Diabetes
- Inability to lie flat on camera bed for about two and a half hours
- Pregnant or breastfeeding
- Current substance use disorder based on DSM-5
- NIMH employees and staff and their immediate family members will be excluded from the study per NIMH policy.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
National Institutes of Health Clinical Center
Bethesda, Maryland, 20892
About this study
This study will use magnetic resonance spectroscopy (MRS) to measure in the brain the transfer of [13]C as it is naturally metabolized from glucose to specific chemical transmitters. From this method, we can measure the rate of production of an important excitatory neurotransmitter (glutamate) as well as an inhibitory neurotransmitter (GABA).
Read the detailed description
13C is a stable (i.e., non-radioactive) isotope of carbon with a natural abundance of approximately 1%. Following infusion of [13C]glucose and/or [13C]acetate, in vivo MRS (magnetic resonance spectroscopy) can monitor the rate of flux of the 13C atom from glucose and/or acetate to glutamate to glutamine. Thus, this procedure can provide measure of glutamate (GLU) and glutamine (GLN) turnover in brain. We have established parameters to obtain these measurements in nonhuman primate brain. The current protocol seeks approval to optimize MRS parameters and to develop new MRS techniques for human brain using the GE 3T, the Siemens 3T, and the Siemens 7T device.
Study population: All subjects will be aged 18 - 65 years, without serious medical illnesses and meet criteria listed under 'Subjects'.
Design: Subjects will receive either oral administration of [13C]glucose or an intravenous infusion of [13C]glucose and/or [13C]acetate to approximately double their plasma glucose levels. The plasma acetate level will remain within the physiological range observed in humans. While lying in the 3T or 7T device, serial data acquisitions will be obtained over approximately 2 h to optimize the experimental conditions so as to measure the 13C signals from GLU, GLN and other metabolisms in brain.
Outcome measures: The primary goal of this study is to measure GLU/GLN turnover in brain. With no additional data acquisition, we can also obtain information on the synthesis of GABA, the major inhibitory neurotransmitter in brain. GLU is converted to GABA via the enzyme glutamic acid decarboxylase (GAD). While monitoring the transfer of 13C signal from GLU to GLN, we can simultaneously measure the transfer of 13C signal from GLU to GABA and thereby measure the activity of GAD. In addition to directly measure 13C signals, 13C labeling to brain metabolites can also be measured indirectly by detecting proton MRS during infusion of [13C]glucose and/or [13C]acetate.
- Conditions
- Normal Physiology
- Being tested
- 3T and 7T device
- Keywords
- Glutamate, Excitatory Amino Acid, Neurochemistry, Brain, Magnetic Resonance Spectroscopy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
3T and 7T deviceDevice
3T and 7T device
| Study group | Role | What they receive |
|---|---|---|
| One arm | Other | Subjects receive the same test Receives: Device: 3T and 7T device |
What is being measured
The primary outcome is the main question the study is designed to answer.
The primary outcome is the quality of the MR spectroscopy which includes spectrum signal-to-noise (SNR)\ ratio, spectral lineshape, linewidth, and resolution.
To obtain more accurate and reliable MRS data from the human brain
Measured: prospective and ongoing
Secondary outcomes (1)
The secondary outcome is the performance improvements of the scanner hardware, software and methodology
To obtain more accurate and reliable MRS data from the human brain.
Measured: prospective and ongoing
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Apr 2005 (estimated)
- Study start6 Sep 2006
- Primary completion11 Jan 2030 (estimated)
- Study completion11 Mar 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Normal PhysiologyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- National Institute of Mental Health (NIMH)
- Sponsor type
- US National Institutes of Health
- Responsible party
- Sponsor
- Investigators
- Li An, Ph.D., Principal investigator, National Institute of Mental Health (NIMH)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00109174
- Sponsor's protocol ID
- 050144
- Other IDs
- 05-M-0144
- Status last verified
- 9 Sep 2026
- First submitted
- 22 Apr 2005
- Last updated
- 13 Oct 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No