Tawa Masashi, Shimosato Takashi, Sakonjo Hiroshi, Okamura Tomio
Department of Pharmacology, Shiga University of Medical Science, Otsu, Japan.
Pharmacology. 2017;99(5-6):275-280. doi: 10.1159/000461587. Epub 2017 Mar 2.
BACKGROUND/AIMS: Nitroglycerin is widely used as a coronary vasodilator in the treatment of ischemic heart diseases. This study investigated the influence of hypoxia on nitroglycerin-induced relaxation in endothelium-intact and -denuded rabbit, monkey, and porcine coronary arteries.
Helically cut strips of coronary arteries were suspended in organ chambers, and isometric tension was recorded.
Nitroglycerin concentration dependently relaxed endothelium-intact rabbit coronary arteries, which were not different under normoxic and hypoxic conditions. On the other hand, nitroglycerin-induced relaxation of endothelium-denuded arteries was significantly attenuated by hypoxia. Similarly, the relaxant response of endothelium-intact monkey coronary arteries to nitroglycerin was not affected by hypoxia, whereas that of endothelium-denuded arteries was impaired. As is the case with rabbit and monkey coronary arteries, exposure to hypoxia resulted in impaired relaxation by nitroglycerin in endothelium-denuded but not endothelium-intact porcine coronary arteries.
These findings suggest that coronary endothelium plays a pivotal role in preventing the hypoxia-induced impairment of nitroglycerin responsiveness, regardless of the animal species.
