Soluble Guanylate Cyclase Redox State Under Hypoxia or Hypoxia/Reoxygenation in Isolated Monkey Coronary Arteries

Journal of Pharmacological Sciences

Ayman Geddawy¹  Tomio Okamura¹  Hirotaka Iwasaki¹  Masashi Tawa¹  Takashi Shimosato¹  Takeshi Imamura¹ 

[1] Department of Pharmacology, Shiga University of Medical Science, Japan

关键词: soluble guanylate cyclase;    cGMP;    hypoxia;    reoxygenation;    coronary artery;   

DOI  :  10.1254/jphs.14046FP

学科分类：药学

来源: Nihon Yakuri Gakkai Henshuubu / Japanese Pharmacological Society

【 摘 要 】

References(31)Cited-By(8)Supplementary materials(1)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.

【 授权许可】

Unknown