Multinuclear Spectroscopy of Rat Brain

Different multinuclear spectroscopy methods for rat brain have been developed on an 11.7T vertical magnet with bore size of 89mm. They include (1) single-shot, INEPT-based ¹H-¹³C polarization transfer method with 3D proton localization and (2) proton observed carbon-13 edited (POCE) method. Spectra with excellent SNR and high spectral resolution have been obtained with these methods. The methods can be applied to measure the turnover kinetics of glutamate, glutamine, aspartate, GABA and other metabolites from intravenously infused ¹³C labeled substrate.

Accumulated in vivo ¹³C spectrum acquired using the improved INEPT sequence during infusion of [1,6-¹³C₂]glucose. A 5 Hz exponential line-broadening was applied.

The time-course spectra for the proton-observed, ¹³C-edited (POCE) and decoupled spectroscopy experiment. The pulse sequence was similar to that used in the proton-only spectroscopy experiment except that a ¹³C editing pulse for subtraction of protons attached to ¹²C and WALTZ-4 ¹³C decoupling were added. TR/TE = 2700/22 ms and NA = 512. The result shows that the turnover kinetics of glutamate, glutamine and GABA can be simultaneously determined.