Metabolic aspects of aging brain and related disorders.

In this report we summarize some of our findings obtained with single photon emission computed tomography (SPECT) in man and with 19F nuclear magnetic relaxation (19FNMR) and (14C) deoxyglucose ([14C]DG) techniques in animals. 99Tc-hexamethyl-propyleneamineoxime (99Tc-HM-PAO) SPECT showed a pattern of decreased cerebral perfusion in Alzheimer and Parkinson patients without clinical and instrumental signs of cerebrovascular diseases. Rat cerebral cortex superoxide dismutases (SODs) concentrations, as detected with 19FNMR, increased in an age-related fashion. These increases may constitute a self-protecting mechanism of the brain against the parallel elevations of free radical reactions observed during aging. The specific neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) elevated ([14C]DG) uptake in catecholaminergic regions of the mouse brain. These effects could be prevented by pretreatment with l-deprenyl. Our results suggest that excitotoxic mechanisms may participate in the neurotoxic effect of MPTP and they can be abolished by the monoamine-oxidase B (MAO-B) inhibitor.