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Titolo:
ARGININE-VASOPRESSIN REDUCES THE BLOOD-BRAIN TRANSFER OF L-TYROSINE AND L-VALINE - FURTHER EVIDENCE OF THE EFFECT OF THE PEPTIDE ON THE L-SYSTEM TRANSPORTER AT THE BLOOD-BRAIN-BARRIER
Autore:
REICHEL A; BEGLEY DJ; ERMISCH A;
Indirizzi:
UNIV LEIPZIG,BIOSCI SECT,TALSTR 33 D-04103 LEIPZIG GERMANY UNIV LONDON KINGS COLL,DIV BIOMED SCI LONDON WC2R 2LS ENGLAND
Titolo Testata:
Brain research
fascicolo: 1-2, volume: 713, anno: 1996,
pagine: 232 - 239
SICI:
0006-8993(1996)713:1-2<232:ARTBTO>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
RAT HIPPOCAMPUS; AMINO-ACIDS; L-LEUCINE; KINETICS; FLOW;
Keywords:
AMINO ACID TRANSPORT; ARGININE VASOPRESSIN; BLOOD-BRAIN BARRIER; KINETIC CONSTANT; L-SYSTEM; TYROSINE; VALINE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
A. Reichel et al., "ARGININE-VASOPRESSIN REDUCES THE BLOOD-BRAIN TRANSFER OF L-TYROSINE AND L-VALINE - FURTHER EVIDENCE OF THE EFFECT OF THE PEPTIDE ON THE L-SYSTEM TRANSPORTER AT THE BLOOD-BRAIN-BARRIER", Brain research, 713(1-2), 1996, pp. 232-239

Abstract

Arginine vasopressin (AVP) coinjected into the carotid artery in physiological concentrations (0.1 nmol/l), with either L-[H-3]tyrosine or L-[H-3]valine, induced changes in the kinetic parameters of the blood-to-brain transfer of both large neutral amino acids (LNAA) without alterations in brain haemodynamics. The half-saturation constant (K-m), the maximum velocity of transport (V-max) and K-d, the nonsaturable transport constant, were estimated in 9 brain regions of male Wistar ratsanaesthetized with ether. Apart from K-d, significant changes in K-m and V-max were observed in all brain regions investigated. On average K-m decreased from 0.17 to 0.048 mmol/l for tyrosine, and from 0.61 to0.059 mmol/l for valine, whereas V-max declined from 22 to 9.9 nmol/min/g for tyrosine, and from 29 to 3.2 nmol/min/g for valine, respectively. The results provide further evidence that vasopressin-receptor interactions at the blood-brain barrier (BBB) induce changes in the properties of the common transporter, the L-system, which eventually result in a suppression of the blood-to-brain transfer of LNAA. Data analysis of the 5 LNAA tested so far reveals a significant negative correlation (R = 0.98, P < 0.05) between the respective substrate affinity forthe transporter and the corresponding magnitude of transport reduction induced by circulating AVP. Calculations of the unidirectional influx (J) of the LNAA indicate that AVP (1) reduces J by approximately one-third for every LNAA, but (2) does not change the relative contribution for each single LNAA to the total influx across the BBB.

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Documento generato il 28/01/21 alle ore 07:31:35