Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/31281
Type: Artigo de periódico
Title: NAA and NAAG variation in neuronal activation during visual stimulation
Author: Castellano, G.
Dias, C.S.B.
Foerster, B.
Li, L.M.
Covolan, R.J.M.
Abstract: N-acetyl-aspartyl-glutamate (NAAG) and its hydrolysis product N-acetyl-L-aspartate (NAA) are among the most important brain metabolites. NAA is a marker of neuron integrity and viability, while NAAG modulates glutamate release and may have a role in neuroprotection and synaptic plasticity. Investigating on a quantitative basis the role of these metabolites in brain metabolism in vivo by magnetic resonance spectroscopy (MRS) is a major challenge since the main signals of NAA and NAAG largely overlap. This is a preliminary study in which we evaluated NAA and NAAG changes during a visual stimulation experiment using functional MRS. The paradigm used consisted of a rest period (5 min and 20 s), followed by a stimulation period (10 min and 40 s) and another rest period (10 min and 40 s). MRS from 17 healthy subjects were acquired at 3T with TR/TE = 2000/288 ms. Spectra were averaged over subjects and quantified with LCModel. The main outcomes were that NAA concentration decreased by about 20% with the stimulus, while the concentration of NAAG concomitantly increased by about 200%. Such variations fall into models for the energy metabolism underlying neuronal activation that point to NAAG as being responsible for the hyperemic vascular response that causes the BOLD signal. They also agree with the fact that NAAG and NAA are present in the brain at a ratio of about 1:10, and with the fact that the only known metabolic pathway for NAAG synthesis is from NAA and glutamate.
Subject: Proton magnetic resonance spectroscopy
Functional experiments
Brain activation
Brain energy metabolism
N-acetyl-L-aspartate
N-acetyl-aspartyl-glutamate
Editor: Associação Brasileira de Divulgação Científica
Rights: aberto
Identifier DOI: 10.1590/S0100-879X2012007500128
Address: http://dx.doi.org/10.1590/S0100-879X2012007500128
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012001100006
Date Issue: 1-Nov-2012
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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