J. Tamaoki et al., CYCLIC ADENOSINE MONOPHOSPHATE-MEDIATED RELEASE OF NITRIC-OXIDE FROM CANINE CULTURED TRACHEAL EPITHELIUM, American journal of respiratory and critical care medicine, 152(4), 1995, pp. 1325-1330
Citations number
36
Categorie Soggetti
Emergency Medicine & Critical Care","Respiratory System
Nitric oxide (NO) may play a part in pulmonary vascular regulation and
bronchomotor control and has been detected in exhaled air. We report
the release of NO from airway epithelial cells and its regulation by c
yclic adenosine monophosphate (cAMP). To directly measure NO release,
a highly specific amperometric sensor for NO made of Pt/Ir alloy coate
d with a three-layered membrane consisting of KCl, NO-selective resin,
and normal silicon resin was developed. Immersion of this sensor in t
he medium containing canine cultured tracheal epithelium detected base
line levels of NO at 9.6 +/- 1.6 nM (mean +/- SE), which was reduced b
y N-G-nitro-L-arginine methylester (L-NAME) but not by D-NAME. This in
hibition was reversed by L-arginine. Addition of isoproterenol, 3-isob
utyl-1-methylxanthine, a nd forskolin caused a rapid increase in NO, a
n effect that was not altered by Ca2+-free medium in the presence of t
he intracellular Ca2+ chelator BAPTA-AM and the calmodulin antagonist
W-7. Bradykinin, ionomycin, and ATP were without effect on NO release.
The forskolin-induced NO release was accompanied by intracellular acc
umulation of cAMP and Ca2+. In contrast, bradykinin increased intracel
lular Ca2+ but not cAMP levels. Cytochemistry of cultured tracheal epi
thelium showed a positive staining with NADPH diaphorase activity. The
se results suggest that airway epithelial cells spontaneously release
NO and that the release may be stimulated specifically through a cAMP-
dependent mechanism.