Quantitative H-1 and P-31 MRS of PCA extracts of postmortem Alzheimer's disease brain

Several previous studies have shown metabolic abnormalities in perchloric acid extracts of postmortem Alzheimer's disease (AD) brain by both proton (H-1) and phosphorus-31 (P-31) magnetic resonance spectroscopy (MRS). In all of these studies the results were expressed in relative terms, in units of mol percent. The results of this study, expressed in the absolute units of mu mol/g wet weight, verify the previous H-1 and P-31 MRS studies. Absolute increases were found for myo-inositol, aspartate, L-glutamate, alanine, phosphocholine, and the phosphodiesters,. Absolute decreases were found for phosphoethanolamine and N-acetyl-l-aspartate. Many of these changes also were observed in non-AD dementia brain extracts, bur changes in myo-inositol, inositol-1-phosphate, aspartate, and L-glutamate appeared to be more specific for AD in extracts of many brain areas. These results suggest that compounds related to membrane degradation and excitatory neurotransmission increase in Alzheimer's disease while compounds related to neuronal integrity and inhibitory neurotransmission are decreased.