Figure 6.

Neuronal and astrocytic metabolism in the spinal cord of FVB/Twitcher (Twi) mice and controls. Twi mice and wild-type (WT) littermates were injected at PND30 and PND40 with [1-¹³C]glucose and [1,2-¹³C]acetate and brain extracts were analyzed by ¹³C and ¹H MRS. (A–H) Approximately 70% of [2-¹³C]Acetyl CoA, which is derived from [1-¹³C]glucose, is metabolized in the neuronal TCA cycle.⁴⁰ Thus [1-¹³C]glucose-derived label in [4-¹³C]glutamine, [4-¹³C]glutamate, [2-¹³C]GABA and [3-¹³C]aspartate mainly represents neuronal metabolism. (A, C, E, G) Amount of labeled glutamine, glutamate, GABA and aspartate (nmol/g tissue). (B, D, F, H) Percent enrichment of the respective ¹³C isotopomer. (I–N) Acetate is preferentially metabolized in glial cells. Hence [1,2-¹³C]acetate-derived label in [4,5-¹³C]glutamine, [4,5-¹³C]glutamate and [1,2-¹³C]GABA exclusively monitors astrocytic metabolism. (I, K, M) Amount of label (nmol/g tissue). (J, L, N) Percent enrichment of the respective ¹³C isotopomer. Data represent mean±s.e.m., n=6 mice/group. One-way analysis of variance and Fisher's least significant difference post hoc tests, *P⩽0.05, statistically significant from WT. Dotted lines indicate a statistically significant difference between PND30 and PND40.