Premium
Quantification of amounts and 13 C content of metabolites in brain tissue using high‐ resolution magic angle spinning 13 C NMR spectroscopy
Author(s) -
Risa Øystein,
Melø Torun Margareta,
Sonnewald Ursula
Publication year - 2009
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1317
Subject(s) - nuclear magnetic resonance spectroscopy , magic angle spinning , chemistry , perchloric acid , glutamine , creatine , phosphocreatine , nmr spectra database , spectroscopy , nuclear magnetic resonance , chromatography , amino acid , biochemistry , stereochemistry , spectral line , biology , physics , organic chemistry , quantum mechanics , astronomy , endocrinology , energy metabolism
Metabolic pathway mapping using 13 C NMR spectroscopy has been used extensively to study interactions between neurons and glia in the brain. Established extraction procedures of brain tissue are time consuming and may result in degradation of labile substances. We examined the potential of mapping 13 C‐enriched compounds in intact brain tissue using high‐resolution magic angle spinning (HR‐MAS) NMR spectroscopy. Sprague–Dawley rats received an intraperitoneal injection of [1,6‐ 13 C]glucose, and 15 min later the animals were subjected to microwave fixation of the brain. Quantification of concentration and 13 C labelling of metabolites in intact rat thalamus were carried out based on exogenous ethylene glycol concentrations measured from 1 H NMR spectra using an ERETIC (Electronic REference To access In vivo Concentrations) signal. The results from intact tissue were compared with those from perchloric acid‐extracted brain tissue. Amounts of 13 C labelling at different positions (C2, C3 and C4) in glutamate, glutamine, γ‐ aminobutyric acid and aspartate measured in either intact tissue or perchloric acid extracts were not significantly different. Proton NMR spectra were used for quantification of six different amino acids plus lactate, inositol, N ‐acetylaspartate, creatine and phosphocreatine. Again, results were very similar when comparing the methods. To our knowledge, this is the first time quantitative 13 C NMR spectroscopy measurements have been carried out on intact brain tissue ex vivo using the HR‐MAS technique. The results show that HR‐MAS 13 C NMR spectroscopy in combination with 1 H NMR spectroscopy and the ERETIC method is useful for metabolic studies of intact brain tissue ex vivo . Copyright © 2008 John Wiley & Sons, Ltd.