title: Inhibition of L-[18F]fluorodopa uptake into human brain by amino acids demonstrated by positron emission tomography.
abstract: The brain uptake of L-[18F]fluorodopa was measured by positron emission tomography in a healthy male volunteer both under fasting conditions and during intravenous amino acid loading. A significant reduction of tracer uptake into the brain was demonstrated with amino acid loading. This finding represents the first direct evidence for competition between L-dopa and other amino acids for uptake across the blood-brain barrier obtained in vivo in a human subject. It underlines the possible importance of interference by dietary amino acids with the therapeutic actions of L-dopa in Parkinson's disease.
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000494:pharmacology*; D001812:Blood-Brain Barrier; D001921:Brain / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism; D003864:Depression, Chemical; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives / Q000378:metabolism*; D006801:Humans; D008297:Male; D014055:Tomography, Emission-Computed
chemical_list: D000596:Amino Acids; D004295:Dihydroxyphenylalanine