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Titolo:
INHIBITION OF NEUTRAL AMINO-ACID-TRANSPORT ACROSS THE HUMAN BLOOD-BRAIN-BARRIER BY PHENYLALANINE
Autore:
SHULKIN BL; BETZ AL; KOEPPE RA; AGRANOFF BW;
Indirizzi:
UNIV MICHIGAN,SCH MED,DEPT INTERNAL MED,DIV NUCL MED,5605 KRESGE RES I ANN ARBOR MI 48109 UNIV MICHIGAN,SCH MED,DEPT INTERNAL MED,DIV NUCL MED ANN ARBOR MI 48109 UNIV MICHIGAN,SCH MED,DEPT PEDIAT ANN ARBOR MI 00000 UNIV MICHIGAN,SCH MED,DEPT SURG NEUROSURG ANN ARBOR MI 00000 UNIV MICHIGAN,SCH MED,DEPT NEUROL ANN ARBOR MI 00000 UNIV MICHIGAN,SCH MED,DEPT PSYCHIAT ANN ARBOR MI 00000 UNIV MICHIGAN,SCH MED,DEPT BIOL CHEM ANN ARBOR MI 48109 UNIV MICHIGAN,SCH MED,MENTAL HLTH RES INST ANN ARBOR MI 48109
Titolo Testata:
Journal of neurochemistry
fascicolo: 3, volume: 64, anno: 1995,
pagine: 1252 - 1257
SICI:
0022-3042(1995)64:3<1252:IONAAT>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
POSITRON EMISSION TOMOGRAPHY; PERFUSION TECHNIQUE; CAPILLARIES; LEVODOPA; KINETICS;
Keywords:
AMINOCYCLOHEXANECARBOXYLATE; POSITRON EMISSION TOMOGRAPHY; L-SYSTEM TRANSPORTER; ESSENTIAL AMINO ACIDS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
29
Recensione:
Indirizzi per estratti:
Citazione:
B.L. Shulkin et al., "INHIBITION OF NEUTRAL AMINO-ACID-TRANSPORT ACROSS THE HUMAN BLOOD-BRAIN-BARRIER BY PHENYLALANINE", Journal of neurochemistry, 64(3), 1995, pp. 1252-1257

Abstract

The delivery of large neutral amino acids (LNAAs) to brain across theblood-brain barrier (BBB) is mediated by the L-type neutral amino acid transporter present in the membranes of the brain capillary endothelial cell. In experimental animals, the L-system transporter is saturated under normal conditions, and therefore an elevation in the plasma concentration of one LNAA will reduce brain uptake of others. In this study, we used positron emission tomography (PET) to determine the effect of elevated plasma phenylalanine concentrations on the uptake of anartificial neutral amino acid, [C-11]-aminocyclohexanecarboxylate ([C-11]ACHC), in human brain. PET scans were performed on six normal malesubjects after an overnight fast and again 60 min after oral administration of 100 mg/kg of phenylalanine. The plasma phenylalanine concentration increased by an average of 11-fold between the first and secondscans. This increase produced a reduction in [C-11]ACHC uptake in allbrain regions but not in scalp. The mean +/- SD influx rate constant for whole brain decreased after phenylalanine ingestion from 0.036 +/-0.002 to 0.019 +/- 0.004 ml/gl min. Kinetic analysis of the effect ofplasma phenylalanine concentration on the rate of [C-11]ACHC uptake is compatible with a model of competitive inhibition so that large increases in the concentration of one LNAA in plasma will reduce the brainuptake of other LNAAs across the human BBB.

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Documento generato il 28/01/21 alle ore 07:52:20