A correlative study on hippocampal cation shifts and amino acids and clinico-pathological data in Alzheimer's disease.

Amino acid transmitters and cations were assessed in the frontal cortex and hippocampus of 12 Alzheimer's disease (AD), 4 multi-infarct dementia (MID) patients, and 12 age-matched controls. In the hippocampus, but not in the frontal cortex of AD patients we observed an increase of sodium (Na) and a decrease of potassium (K) and magnesium (Mg) content as compared to controls. Calcium (Ca) was not changed. These cation shifts were highly correlated with glutamate, which was significantly decreased in AD hippocampus. Hippocampal Na and K levels correlated also highly with gamma-aminobutyrate, cholineacetyltransferase and noradrenaline levels in the hippocampus and dementia scores. These results show that Na and K changes are sensitive markers for neurodegenerative processes in AD and suggest a loss of glutamatergic neurons in AD hippocampus.