The activation of nitric oxide synthase by copper ion is mediated by intracellular Ca2+ mobilization in human pulmonary arterial endothelial cells.
The aim of the study was to elucidate the vasodilatory mechanism due to Cu2+ by assessing nitric oxide (NO) production as determined by NOx (NO, NO2-, and NO3-) that is released from human pulmonary arterial endothelial cell (HPAEC) monolayers using a NO chemiluminescence analyzer, and also to assess Ca2+ movement using 45Ca and fura 2 in HPAEC. Cu2+ (10(-6)-10(-4) M) significantly increased NO production in a dose-dependent manner when extracellular Ca2+ was present. 45Ca influx into the adherent cells was dose-dependently enhanced by Cu(2+) (10(-6)-10(-4) M), but not by Mn(2+), Zn(2+) or Fe(2+). [Ca2+]i, measured by monitoring the fluorescence changes of fura 2, was significantly elevated in the presence of Cu2+. The increase in [Ca2+]i induced by Cu2+ was inhibited by either diethyldithiocarbamate (DDC) or the depletion of extracellular Ca2+. The dihydropyridine receptor agonist, BayK8644, significantly attenuated the Cu2+-induced increase in [Ca2+]i in a dose dependent manner and nitrendipine or nifedipine, the dihydropyridine receptor antagonists, dose-dependently inhibited a Cu2+-induced increase in [Ca2+]i. These results suggest that Cu2+ activates eNOS through the mechanism of [Ca2+]i elevation due to Ca2+ influx into HPAEC and that the Cu2+-induced [Ca2+]i elevation in HPAEC is likely due to activation of the dihydropyridine-like receptors.
Demura
Y
Y
Third Department of Internal Medicine, Fukui Medical University, Japan.
Ishizaki
T
T
Ameshima
S
S
Okamura
S
S
Hayashi
T
T
Matsukawa
S
S
Miyamori
I
I
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D002118:Calcium / Q000378:metabolism* / Q000493:pharmacokinetics; D002250:Carbon Radioisotopes; D002412:Cations; D002478:Cells, Cultured; D003300:Copper / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D004789:Enzyme Activation; D004790:Enzyme Induction; D006801:Humans; D008345:Manganese / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000187:drug effects* / Q000378:metabolism*; D011651:Pulmonary Artery / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*
D002250:Carbon Radioisotopes; D002412:Cations; D009569:Nitric Oxide; D008345:Manganese; D015121:6-Ketoprostaglandin F1 alpha; D003300:Copper; D019001:Nitric Oxide Synthase; D002118:Calcium