Approaches to studies on neuronal/glial relationships by 13C-MRS analysis.
The use of different 13C-labelled precursors alone or in combination ([1-13C]glucose, [2-13C]glucose, [1-13C]acetate, [2-13C]acetate and [1,2-13C2]acetate) to study neuronal/glial metabolic relationships by MRS is discussed. Glutamine and citrate resonances represent glial metabolism if a combination of [1-13C]glucose + [2-13C]acetate is used, but only for short time periods. A combination of [2-13C]glucose + [2-13C]acetate will label -COO- groups from glucose and -CH2 groups from acetate, respectively, which distinguish well in theory. However, this approach is severely limited by the long T1S of -COO- groups and low S/N. Contributions of the anaplerotic pathway can be assessed using [2-13C]glucose, but again can be limited by the long T1S of -COO- groups. Labelling of glycerol-3-phosphate (believed to be produced in glia) from [1-13C]glucose is difficult to see under normal conditions but has proved useful in, e.g., hypoxia. We believe the most promising approach is the use of [1-13C] glucose with [1,2-13C2]acetate, by analysis of the multiplets ('isotopomers') of the amino acid resonances.
Taylor
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A
Department of Physics, University of Nottingham, UK.
McLean
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M
Morris
P
P
Bachelard
H
H
D000085:Acetates / Q000378:metabolism; D000818:Animals; D002247:Carbon Isotopes; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D005947:Glucose / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D005994:Glycerophosphates / Q000378:metabolism; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D009457:Neuroglia / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D011766:Pyruvate Carboxylase / Q000378:metabolism
D000085:Acetates; D002247:Carbon Isotopes; D005994:Glycerophosphates; D018698:Glutamic Acid; C029620:alpha-glycerophosphoric acid; D011766:Pyruvate Carboxylase; D005947:Glucose