title: Modulation of mitochondrion-mediated oxidative stress by nitric oxide in human placental trophoblastic cells.
abstract: Intracellular hydroperoxide generation in cultured human placental trophoblastic cells (HPTCs) was quantitatively monitored in the presence or absence of an NO synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME, 1 mM), by digital microfluorography with use of carboxydichlorofluorescein, a hydroperoxide-sensitive fluorogenic probe. In the absence of L-NAME, HPTCs displayed a time-dependent gradual elevation of the fluorescence, suggesting the ability to produce oxidants spontaneously. In the presence of L-NAME, however, the fluorescent response in these cells increased further; the oxidative impact elicited by L-NAME treatment for 30 min was equivalent to that induced by application of 230 microM tert-butyl hydroperoxide for 5 min. This oxidative process was completely blocked by rotenone, a reagent that interferes with electron entry into complex I of the mitochondrial respiratory chain. On the other hand, antimycin A, which blocks mitochondria at the distal site of the ubiquinone pool, potentiated the L-NAME-induced oxidative change. These findings suggest that constitutive levels of nitric oxide production contribute to regulation of mitochondrion-derived intracellular oxidant generation in HPTCs.
authors.affiliation: Department of Biochemistry, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Goda
authors.forename: M
authors.initials: M
authors.lastname: Suematsu
authors.forename: M
authors.initials: M
authors.lastname: Mukai
authors.forename: K
authors.initials: K
authors.lastname: Kiyokawa
authors.forename: M
authors.initials: M
authors.lastname: Natori
authors.forename: S
authors.initials: S
authors.lastname: Nozawa
authors.forename: Y
authors.initials: Y
authors.lastname: Ishimura
mesh_terms: D002469:Cell Separation; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007501:Iron / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000502:physiology*; D010101:Oxygen Consumption; D010920:Placenta / Q000166:cytology / Q000502:physiology*; D011247:Pregnancy; D014327:Trophoblasts / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D007501:Iron; D019331:NG-Nitroarginine Methyl Ester