Peroxynitrite (ONO2) is a noxious metabolite of nitric oxide previously shown to relax arteries during normoxia; however the vascular effects of ONO2 during hypoxia or reperfusion have not been examined. We investigated the influence of ONO2 on canine coronary arteries suspended in organ chambers during normoxia (5%CO2/95%O2), hypoxia (5%CO2/95%N2) and after a 15min hypoxic insult. Arteries were stretched to optimal length-tension and prostaglandin F2α (2×10-6M) contracted Vessels maintained at normoxia relaxed completely to ONO2 (10-9-10-5M, n=5), and similar ONO2-induced relaxations occurred in endothelial-denuded arteries (n=4). Arteries exposed to hypoxia after precontraction also relaxed in a similar fashion (n=5, P=NS, ANOVA). Arteries were exposed to a hypoxic insult for 15min, reoxygenated for 15min, and then contracted. Relaxation to ONO2 was similar to controls maintained in normoxia for the same period of time (n=4). Methylene blue was added prior to ONO2 dose-response curves in paired experiments. Mild attenuation of the relaxation was noted in all groups (n=4, P=NS). This study demonstrates peroxynitrite-induced relaxations during normoxia, hypoxia, or after a 15min hypoxic insult which are not altered by inhibition of soluble guanylate cyclase.
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology