Akademik Veri Yönetim Sistemi
7th european congress of pharmacology, İstanbul, Türkiye, 26 - 30 Haziran 2016, ss.317
S-nitrosothiols (RSNOs) are thought to represent the circulating reservoir of nitric oxide
(NO). S-nitrosoglutathione (GSNO) is an endogenous S-nitrosothiol which suggested to be a
potent vasodilator with a prolonged relaxant effect compared to the current NO donors that
clinically used. There are limited studies about its vascular effects on human vessels while no
data is available on its mechanism of action. In this study, we aimed to investigate the acute
effect of GSNO on human saphenous vein rings as well as the possible underlying
mechanisms.
Isolated human saphenous veins obtained from coronary artery bypass surgery, were
mounted in an organ bath system, aerated with %5CO2 + %95o
2 at 37o
C with a resting
tension of 2g. The effect of GSNO (10-8
-10-4
M) were studied in a concentration-dependent
manner on rings precontracted submaximally with phenylephrine (3x10-5
M). In order to
analyse its mechanism of action, the effects of GSNO were studied in the absence and
presence of NO synthase inhibitor, L-NAME (10-4
M, 30min), soluble guanylyl cyclase (sGC)
inhibitor, ODQ (10-5
M, 30min) or a selective inhibitor of ATP-sensitive K+ channels (KATP),
glibenclamide (10-5
M, 30min).
GSNO produced concentration-dependent relaxant effects on precontracted human
saphenous veins (Emax: 102,40±1,37%). The prominent relaxant influence of GSNO was not
altered in the presence of the inhibitor of NO synthase or KATP channels. While, a significant
decrease was observed with ODQ (ODQ-Emax: 43,73±8,61%; Control-Emax:108,4±4,76%,
p<0.001, n=5)
Our results indicate that acute relaxant effects of GSNO in isolated human saphenous vein
were neither mediated by KATP channel activation nor endogenous NO. Whereas, the
activation of sGC pathway is likely be involved in this response. A better understanding of
the mechanism regulating the vasorelaxant effect of GSNO and its possible role as a new
antispasmodic agent for bypass graft spasms will provide us new therapeutic opportunities.
Keywords: S-nitrosoglutathione, nitric oxide, coronary artery bypass graft, human
saphenous vein