Figure 2.

Three representative ¹³C NMR spectra are shown for Perchloric Acid (PCA) Extracts from slices taken from the superfusion chamber at different times: (A) before hypoxia-ischemia; (B) at the end of hypoxia-ischemia; (C) after four hours of recovery following hypoxia-ischemia. Resonances for particular metabolites are numbered: 1) lactate C3, which is substantially increased in B and C relative to A ; 2) β−hydroxybutyrate C4; 3) GABA C3; 4) glutamate C3; 5) glutamate C4; 6) succinate C2, C3; 7) GABA C2; 8) taurine. (D) a different portion of the same spectrum shown in C, showing an increased resonance peak for C2 of lactate, which is barely discernable in (E). (F) A representative portion of a ¹H spectrum at the end of hypoxia-ischemia. The large, narrow doublet at 1.33 ppm is from the methyl protons on the C3 of unlabeled lactate. When the C3 of lactate is labeled with ¹³C, two doublets occur as indicated by arrows instead of the narrow doublet at 1.33 ppm. In all spectra where ¹³C-glucose is was not used, the combined area of the two small doublets was 1.1% of the large central doublet, which is what occurs from natural abundance ¹³C.