Abstract
This study explored the utility of ^1^H and ^13^C magnetic resonance spectroscopy to study a neuronβenriched preparation made from rat cerebrum. The preparation contained high concentrations of Nβacetylaspartate and Ξ³βaminobutyric acid and low concentrations of glutamine, indicating that it was in fact rich in neuronal cytosol. This was confirmed by immunohistochemical studies with antibodies to neuronal and glial markers. A method of metabolite quantification based on the creatine signal yielded metabolite concentrations similar to those of rat cerebrum, whereas concentrations based on the metabolite/protein ratio were five times lower, suggesting that much protein in the preparation was not associated with functioning cytoplasm. The metabolic competence of the preparation was assessed by quantitative measurements of its ability to convert 1β^13^Cβglucose into lactate, glutamate, aspartate, and other metabolites under well oxygenated conditions for 30 min. Calculated from the creatine standard, the mean glycolytic rate was the same as in a synaptosomal preparation studied under similar conditions and the same as rat cerebrum in vivo. Tricarboxylic acid cycle flux occurred at half the rate observed in the synaptosomal preparation and 16% of the basal cerebral metabolic rate in vivo.