Quantification of amounts and ~(13)C content of metabolites in brain tissue using highresolution magic angle spinning ~(13)C NMR spectroscopy

摘要

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 ~(C1-enriche3d compo)unds 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 ~(l1Cabeling3 of metab)olites in intact rathalamus were caried out based on exogenous ethylene glycol concentrations measured from ~1H 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 ~( l1Cabeling3 at difer)ent positions (C2, C3 and C4) in glutamate, glutamine, γ-aminobutyric acid and aspartate measured in either intactisue 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 1 3CNMR spectroscopy measurements have ben caried out on intact brain tissue ex vivo using the HR-MAS technique. The—results show that HR-MAS 13C NMR spectroscopy in combination with 1 H NMR spectroscopy and the ERETIC method is useful f or metabolic studies of intact brain tissue ex vivo