METABOLIC ALTERATIONS IN BRAIN AUTOPSIES - PROTON NMR IDENTIFICATION OF FREE GLYCEROL

Metabolic alterations in bovine brain homogenate were examined as a fu nction of post mortem interval (PMI) using high-resolution proton NMR spectroscopy, In particular, while lactate, glutamate, glutamine, crea tine and inositols as well as the total concentration of trimethyl-amm onium compounds remained constant, prominent changes due to the hydrol ysis of N-acetylaspartate to acetate and aspartate as well as the deco mposition of glycerophosphocholine into free choline and glycerol corr elated linearly with the duration of PMI (3-195 h). The spectroscopic identification of the latter process was confirmed by proton NMR studi es of model solutions as well as of extracts of mammalian brain showin g high levels of free glycerol, Since the methylene resonances of glyc erol overlap with the proton resonances of myo-inositol, care should b e taken in the interpretation of both in vitro and in vivo brain spect ra.