NMR spectroscopy
13C NMR spectra were run on a Varian VXR-300
spectrometer equipped with a 10mmbroad band probe
and operating at the frequency of 75.4 MHz. Intact portions
of tissues were examined in 10mm NMR tubes
without solvent. Qualitative and quantitative analyses
were performed on 13C spectra acquired using
the NOE-suppressed, inverse-gated proton decoupled
technique (Waltz-16). The free induction decay of each
spectrum was acquired without rotation at 25 ◦C, with
a 1 s acquisition time, using a sweep width of 13 kHz.
One thousand scans were collected using a 90◦ excitation
pulse and a delay of 30 s to allow the complete
relaxation of each 13C signal.