Detection of GABA C1 Turnover in Rat Brain in Vivo

Jehoon Yang^1,2, Jun Shen³

Previous in vivo MRS studies of GABA turnover have relied on ¹³C label incorporation into GABA C2. In this study, the [¹³C]GABA C1 signal at 182.3 ppm in the carboxylic/amide spectral region of localized in vivo ¹³C spectra was spectrally resolved and detected in the rat brain at 11.7 Tesla using low RF power proton decoupling. GABA-transaminase of rat brain was inhibited by gabaculine after pre-labeling of GABA C1 and its precursors with [2,5-¹³C₂]glucose. A subsequent isotope chase experiment revealed a markedly slow turnover of GABA accompanying the blockade of the GABA shunt.