Effects of chronic noradrenaline on the nitric oxide pathway in human endothelial cells.
Altered endothelium-dependent vasodilation has been observed in congestive heart failure (CHF), a disease characterized by a sustained adrenergic activation. The purpose of our study was to test the hypothesis that chronically elevated catecholamines influence the nitric oxide (NO) pathway in the human endothelium. Human umbilical vein endothelial cells (HUVEC) were exposed for 7 days to a concentration of noradrenaline (NA, 1 ng/mL) similar to that found in the blood of patients with CHF. Kinetics of endothelial constitutive NO synthase (ecNOS) and inducible NO synthase (iNOS) activity, measured by [3H]L-arginine to [3H]L-citrulline conversion, and protein expression of ecNOS and iNOS, assessed by Western blot analysis, were unaffected by chronic NA treatment. Furthermore, no changes in subcellular fraction-associated ecNOS were found; this indirectly shows that chronic NA did not cause phosphorylation of the enzyme. Moreover, [3H]L-arginine transport through the plasma membrane was conserved in chronically NA-treated cells. The data demonstrate that prolonged in vitro exposure to pathologic CHF-like NA does not affect the L-arginine: NO pathway in human endothelial cells.
Foundation Salvatore Maugeri, Cardiovascular Pathophysiology Research Centre, Gussago, Brescia, Italy.
T
T
Bachetti
L
L
Comini
L
L
Agnoletti
P
P
Pedersini
G
G
Gaia
A
A
Cargnoni
M
M
Bellet
S
S
Curello
R
R
Ferrari
D001120:Arginine / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009638:Norepinephrine / Q000494:pharmacology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D009569:Nitric Oxide; D001120:Arginine; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009638:Norepinephrine