'On-off' phenomenon in Parkinson's disease: relationship between dopa and other large neutral amino acids in plasma.
Administration of a low-protein diet to parkinsonian patients with "on-off" syndromes consistently increased the total daily time of "on" states when compared with a high-protein diet. The clinical effect of the low-protein diet may be due to a marked decrease in the plasma concentration of large neutral amino acids that compete with L-dopa for carrier-mediated transport into the brain.
D000368:Aged; D000596:Amino Acids / Q000097:blood* / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000097:blood* / Q000378:metabolism; D004347:Drug Interactions; D006801:Humans; D008297:Male; D010300:Parkinson Disease / Q000097:blood* / Q000378:metabolism
D000596:Amino Acids; D004295:Dihydroxyphenylalanine