These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Soluble guanylate cyclase redox state under hypoxia or hypoxia/reoxygenation in isolated monkey coronary arteries.
    Author: Tawa M, Geddawy A, Shimosato T, Iwasaki H, Imamura T, Okamura T.
    Journal: J Pharmacol Sci; 2014; 125(2):169-75. PubMed ID: 24859780.
    Abstract:
    Hypoxia or hypoxia/reoxygenation impairs nitric oxide (NO)-mediated relaxation through the increase in superoxide generation in monkey coronary arteries. Soluble guanylate cyclase (sGC), the target enzyme of NO, has been shown to change from the NO-sensitive reduced form to the NO-insensitive oxidized/heme-free form under substantial oxidative stress, so the present study investigated whether hypoxia or hypoxia/reoxygenation influences sGC redox equilibrium. In isolated monkey coronary arteries without endothelium, the relaxation caused by the sGC stimulator BAY 41-2272 (Emax: 93.3% ± 2.2%) was somewhat impaired under hypoxia (Emax: 86.3% ± 2.6%) or hypoxia/reoxygenation (Emax: 86.1% ± 3.2%), whereas that by the sGC activator BAY 60-2770 (Emax: 86.0% ± 3.2%) was significantly augmented under hypoxia (Emax: 94.4% ± 1.3%) or hypoxia/reoxygenation (Emax: 95.5% ± 1.1%). In addition, cGMP formation in response to BAY 41-2272 and BAY 60-2770 was inhibited and stimulated, respectively, under hypoxia or hypoxia/reoxygenation. The effects of hypoxia or hypoxia/reoxygenation on BAY 41-2272- and BAY 60-2770-induced vasorelaxation were completely canceled by the treatment with the superoxide dismutase mimetic tempol. These findings suggest that sGC redox equilibrium in the coronary artery is shifted towards the NO-insensitive form under hypoxia or hypoxia/reoxygenation and that superoxide seems to play an important role in this shift.
    [Abstract] [Full Text] [Related] [New Search]