Figure 5.

Percent enrichment of isotopomers of GABA labeled from metabolism of [2-¹³C]ALCAR in 21 day old rat brain at 15, 30 and 60min after i.p. injection. [2-¹³C]GABA (GABA C2), [3-¹³C]GABA (GABA C3), and [4-¹³C]GABA (GABA C4) are formed via the enzyme glutamic acid decarboxylase from GLU C4, GLU C3 and GLU C2, respectively. Labeled carbon from glutamine can also be readily converted to glutamate and incorporated into GABA. Spectra were obtained on PCA extracts of brain as described in methods. Values are mean ± S.E. of data from n = 5 brains at 15 min, n=6 at 60min, and n = 8 at 120 min. Data were analyzed using one-way ANOVA and Tukey’s post hoc test… Asterisks indicate significant difference between time points, **p<0.001