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Glutamate is the most abundant excitatory neurotransmitter in the human brain, but in vivo imaging of acute fluctuations in glutamatergic levels has not been well established. The purpose of this study was to examine acute changes in glutamate after stimulation with N-acetylcysteine (NAC) using a simultaneous positron emission tomography/magnetic resonance spectroscopy (PET/MRS) approach. Ten healthy adult males were examined in two scanning sessions, and 5g NAC was administered 1 h prior to one of the scan sessions. Simultaneous PET/MR data were acquired using an integrated 3T PET/MR scanner. Glutamate (Glu), glutamine (Gln), and glutamate + glutamine (Glx) levels were assessed from MRS data collected from the basal ganglia with PRESS and from the left prefrontal cortex with PRESS and MEGAPRESS, and mGluR5 binding (BP) was assessed from PET data collected with [F]PSS232. NAC administration was associated with a significant reduction in Glx and Gln in the basal ganglia spectra, and in Glx in the frontal MEGAPRESS spectra (p < 0.05); no differences in [F]PSS232 BP were observed with NAC, although a correlation between pre-/post-treatment Glx and baseline BPnd was found. The MRS-visible Glx signal is sensitive to acute fluctuations in glutamate. The change in Glx was mostly driven by a change in Gln, lending weight to the notion that Gln can provide a proxy marker for neurotransmitter/synaptic glutamate. [F]PSS232 binding is not sensitive to acute glutamate shifts independently, but was associated with the extent of glutamate liberation upon NAC stimulation.
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A double-blind, placebo controlled, crossover study to determine whether a single dose of N-acetylcysteine (a nutritional supplement) can reduce brain glutamate levels in patients with a p...
We investigate the effects of repeated NAC administration on glutamate concentrations in the anterior cingulate cortex (ACC), on neurocognitive functioning, and on neuro-inflammatory param...
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The use of molecularly targeted imaging probes to localize and/or monitor biochemical and cellular processes via various imaging modalities that include RADIONUCLIDE IMAGING; ULTRASONOGRAPHY; MAGNETIC RESONANCE IMAGING; fluorescence imaging; and MICROSCOPY.
Deliberate prevention or diminution of the host's immune response. It may be nonspecific as in the administration of immunosuppressive agents (drugs or radiation) or by lymphocyte depletion or may be specific as in desensitization or the simultaneous administration of antigen and immunosuppressive drugs.
An IBOTENIC ACID homolog and glutamate agonist. The compound is the defining agonist for the AMPA subtype of glutamate receptors (RECEPTORS, AMPA). It has been used as a radionuclide imaging agent but is more commonly used as an experimental tool in cell biological studies.
A syndrome characterized by acute OPTIC NEURITIS in combination with acute MYELITIS, TRANSVERSE. Demyelinating and/or necrotizing lesions form in one or both optic nerves and in the spinal cord. The onset of optic neuritis and myelitis may be simultaneous or separated by several months. (J Neurol Neurosurg Psychiatry 1996 Apr;60(4):382-387)
A PYRIDOXAL PHOSPHATE-containing enzyme that catalyzes the transfer of a formyl group from L-GLUTAMATE to N-formimidoyl-L-glutamate and TETRAHYDROFOLATE. This enzyme may also catalyze formyl transfer from 5-formyltetrahydrofolate to L-GLUTAMATE. This enzyme was formerly categorized as EC 18.104.22.168.