Activation of A2-purinoceptors by adenosine stimulates L-arginine transport (system y+) and nitric oxide synthesis in human fetal endothelial cells

1. Human umbilical vein endothelial cells were challenged acutely with adenosine and its analogues to examine whether adenosine modulates L-arginine transport (system y+) and synthesis of nitric oxide (NO) and prostacyclin (PGI2). 2. L-Arginine transport was stimulated by adenosine (10 microM, 2 min...

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Bibliographic Details
Published in:The Journal of physiology 1997-02, Vol.499 (Pt 1), p.135-140
Main Authors: Sobrevia, L, Yudilevich, D L, Mann, G E
Format: Article
Language:English
Subjects:
Adenosine - pharmacology
Arginine - metabolism
Biological Transport - physiology
Dose-Response Relationship, Drug
Endothelium - metabolism
Fetus - metabolism
Humans
Nitric Oxide Synthase - biosynthesis
Receptors, Purinergic - drug effects
Receptors, Purinergic - physiology
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Summary:1. Human umbilical vein endothelial cells were challenged acutely with adenosine and its analogues to examine whether adenosine modulates L-arginine transport (system y+) and synthesis of nitric oxide (NO) and prostacyclin (PGI2). 2. L-Arginine transport was stimulated by adenosine (10 microM, 2 min) and the A2-receptor agonist 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine (CGS-21680; 100 nM), but not by the A1-receptor agonist N6-cyclopentyladenosine (CPA). 3. Activation of L-arginine transport was inhibited by the A2-receptor antagonists ZM-241385 and 3,7-dimethyl-1-propargylxanthine (DMPX), but unaffected by the A1-receptor antagonists 8-cyclopentyl-1,3-dipropylxanthine and 8-phenyltheophylline or the adenosine transport inhibitor nitrobenzylthioinosine. 4. Adenosine and CGS-21680 evoked a rapid membrane hyperpolarization. 5. Adenosine and CGS-21680 induced increases in intracellular cGMP levels, whereas release of PGI2 was unaffected. NG-nitro-L-arginine methyl ester (an NO synthase inhibitor) and the A2-receptor antagonists ZM-241385 and DMPX prevented increases in cGMP accumulation. 6. Our findings provide the first evidence that activation of human fetal endothelial cell A2-purinoceptors, but not A1-purinoceptors, leads to a membrane hyperpolarization and stimulation of basal rates of L-arginine transport and NO biosynthesis.
ISSN:0022-3751
1469-7793
DOI:10.1113/jphysiol.1997.sp021916