Recruiting INTERVENTIONAL NCT00109174

MRS Measurement of Glutamate and GABA Metabolism in Brain

MRS (Magnetic Resonance Spectroscopy) Measurement of Glutamate and GABA Metabolism in Brain

Sponsor: National Institute of Mental Health (NIMH)

Updated 76 times since 2017 Last updated: Apr 11, 2026 Started: Sep 6, 2006 Primary completion: Jan 11, 2030 Completion: Mar 11, 2030

This information is for research purposes only and is not medical advice. Consult a healthcare provider before making any medical decision.

A observational or N/A phase clinical study on Normal Physiology, this trial is actively recruiting participants. The trial is conducted by National Institute of Mental Health (NIMH) and has accumulated 76 data snapshots since 2006. Longitudinal tracking of this trial contributes to a broader understanding of treatment development timelines.

Study Description(click to expand)

13C is a stable (i.e., non-radioactive) isotope of carbon with a natural abundance of \~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 in Section VI A. 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 (Lebon et al, 2002). While lying in the 3T or 7T device, serial data acquisitions will be obtained over \~2 h to optimize the experimental conditions so as to measure the 13C signals from GLU, GLN and other metabolisms...

Study population: All subjects will be aged 18 65 years, without serious medical illnesses and meet criteria listed in Section VI A.

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 (Lebon et al, 2002). While lying in the 3T or 7T device, serial data acquisitions will be obtained over \~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 (Li et al 2005). 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.

Status Flow

Change History

76 versions recorded

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First recorded

Sep 2006

Trial started

Per CT.gov start date — pre-dates our first snapshot

Eligibility 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. From this method, we can measure the rate of production of an important excitatory neurotransmitter (glutamate) as well as an inhibitory neurotransmitter (GABA)....

Contact Information

Sponsor contact:

National Institute of Mental Health (NIMH)

Data source: ClinicalTrials.gov

For direct contact, visit the study record on ClinicalTrials.gov .

Study Locations

• Bethesda, United States