[A role of glutamate decarboxylase in Alzheimer's disease].

OBJECTIVE: To evaluate the levels of the main GABA synthetic enzyme, glutamate decarboxylase (represented by two isoforms, GAD65 and GAD67) in the cerebellum cortex of patients with Alzheimer's disease (AD) and mentally healthy subjects. MATERIALS AND METHODS: Samples of the cerebellum cortex from 13 mentally healthy subjects (the control group) and 13 patients with AD were studied. Samples obtained after autopsy were frozen and stored at -80 °C. The groups are matched by sex, age, postmortem interval and cause of death. Protein extracts from cerebellum tissues were obtained after removing of nuclei and cell debris by centrifugation and treatment of the obtained fractions with detergent (SDS). Relative amounts of GAD65 and GAD67 were determined using SDS-PAAG-electrophoresis with the following semi-quantitative ECL-Western-immunoblotting with chemiluminescence detection. RESULTS: The amounts of both isoenzymes (GAD65 and GAD67) were significantly reduced in AD samples. CONCLUSION: The decreased amount of both glutamate decarboxylase isoenzymes suggests the decreased synthesis of neurotransmitter and basic GABA pools that indicates insufficient functioning of the GABA system in the cerebellar cortex of AD patients.