Endogenous nitric oxide production modulates mitochondrion
-dependent oxidative stress in cultured human placental trophoblastic
cells .
Goda, Nobuhito, Makoto Suematsu, Makio Mukai, Kaoru Kiyokawa, Michiya
Natori, Shiro Nozawa, and Yuzuru Ishimura.
Departments of Biochemistry, Obstetrics and Gynecology and
Pathology, School of Medicine, Keio University, Tokyo 160
APStracts 3:0195H, 1996.
Intracellular hydroperoxide generation in cultured human placental
trophoblastic cells (HPTCs) was quantitatively monitored in the
presence or absence of a NO synthase inhibitor, NG-nitro-L-arginine
methyl ester (L-NAME; 1 mM) by digital microfluorography using
carboxydichlorofluorescein, a hydroperoxide-sensitive fluorogenic
probe. In the absence of L-NAME, HPTCs displayed time-dependently a
gradual elevation of the fluorescence, suggesting the ability to
produce oxidants spontaneously. In its presence, however, the
fluorescent response in these cells exhibited further increase: The
oxidative impact elicited by L-NAME treatment for 30 min was
equivalent to that induced by application of 230 [mu]M tert-butyl
hydroperoxide for 5 min. This oxidative process was completely
blocked by rotenone, a reagent which interferes with an electron
entry into complex I of 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.
Received 19 December 1995; accepted in final form 24 April 1996.
APS Manuscript Number H1183-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 8 May 96