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Influence of fluctuations of plasma large neutral amino acids with normal diets on the clinical response to levodopa.
J Neurol Neurosurg Psychiatry. 1989 Apr; 52(4):481-7.JN

Abstract

Plasma large neutral amino acids (LNAAs) compete with levodopa for entry into the brain. Fluctuations in plasma LNAA concentrations could therefore contribute to variability in clinical response to levodopa. The hourly plasma levodopa, plasma LNAAs and clinical response were investigated in 11 fluctuating Parkinsonian patients on a regular hospital diet. The fluctuations in plasma levodopa were 2 to 3 times greater than the fluctuations of plasma LNAAs. The correlation between clinical response and plasma levodopa was substantially improved in only one patient by considering plasma LNAAs and calculating relative levodopa flux into brain. Although plasma LNAAs significantly increased during the day, the patients' clinical status did not uniformly deteriorate and mean afternoon clinical scores correlated better with mean plasma levodopa and levodopa flux than with mean plasma LNAAs. Minimum effective concentrations of levodopa for clinical response did not correlate with 9 am LNAA concentrations. It is concluded that in most patients, the relatively small variation in plasma LNAAs in comparison with the large variations in plasma levodopa indicates that fluctuations in LNAA are not an important contributor to the fluctuating response to levodopa.

Authors+Show Affiliations

Department of Neurology, Oregon Health Sciences University, Portland 97201.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

2738591

Citation

Nutt, J G., et al. "Influence of Fluctuations of Plasma Large Neutral Amino Acids With Normal Diets On the Clinical Response to Levodopa." Journal of Neurology, Neurosurgery, and Psychiatry, vol. 52, no. 4, 1989, pp. 481-7.
Nutt JG, Woodward WR, Carter JH, et al. Influence of fluctuations of plasma large neutral amino acids with normal diets on the clinical response to levodopa. J Neurol Neurosurg Psychiatry. 1989;52(4):481-7.
Nutt, J. G., Woodward, W. R., Carter, J. H., & Trotman, T. L. (1989). Influence of fluctuations of plasma large neutral amino acids with normal diets on the clinical response to levodopa. Journal of Neurology, Neurosurgery, and Psychiatry, 52(4), 481-7.
Nutt JG, et al. Influence of Fluctuations of Plasma Large Neutral Amino Acids With Normal Diets On the Clinical Response to Levodopa. J Neurol Neurosurg Psychiatry. 1989;52(4):481-7. PubMed PMID: 2738591.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Influence of fluctuations of plasma large neutral amino acids with normal diets on the clinical response to levodopa. AU - Nutt,J G, AU - Woodward,W R, AU - Carter,J H, AU - Trotman,T L, PY - 1989/4/1/pubmed PY - 1989/4/1/medline PY - 1989/4/1/entrez SP - 481 EP - 7 JF - Journal of neurology, neurosurgery, and psychiatry JO - J Neurol Neurosurg Psychiatry VL - 52 IS - 4 N2 - Plasma large neutral amino acids (LNAAs) compete with levodopa for entry into the brain. Fluctuations in plasma LNAA concentrations could therefore contribute to variability in clinical response to levodopa. The hourly plasma levodopa, plasma LNAAs and clinical response were investigated in 11 fluctuating Parkinsonian patients on a regular hospital diet. The fluctuations in plasma levodopa were 2 to 3 times greater than the fluctuations of plasma LNAAs. The correlation between clinical response and plasma levodopa was substantially improved in only one patient by considering plasma LNAAs and calculating relative levodopa flux into brain. Although plasma LNAAs significantly increased during the day, the patients' clinical status did not uniformly deteriorate and mean afternoon clinical scores correlated better with mean plasma levodopa and levodopa flux than with mean plasma LNAAs. Minimum effective concentrations of levodopa for clinical response did not correlate with 9 am LNAA concentrations. It is concluded that in most patients, the relatively small variation in plasma LNAAs in comparison with the large variations in plasma levodopa indicates that fluctuations in LNAA are not an important contributor to the fluctuating response to levodopa. SN - 0022-3050 UR - https://www.unboundmedicine.com/medline/citation/2738591/Influence_of_fluctuations_of_plasma_large_neutral_amino_acids_with_normal_diets_on_the_clinical_response_to_levodopa_ L2 - https://jnnp.bmj.com/lookup/pmidlookup?view=long&pmid=2738591 DB - PRIME DP - Unbound Medicine ER -