Adenosineの内皮依存性冠血管拡張作用

麻酔開胸犬を用いた検討

抄録

To evaluate the endothelium-dependent coronary vasodilatory effect of adenosine, especially the role of endothelium-derived nitric oxide (EDNO), the dose-response relationship of exogenous adenosine was examined in open-chest dogs before and after intracoronary administration of N^G-nitro-L-arginine (NNLA), a potent inhibitor of NO synthesis.
NNLA attenuated the vasodilatory effect of acetylcholine to less than 25% of the control, which indicates NO synthesis inhibition. NNLA caused a rightward shift of the adenosine dose-response curve with a significant increase of EC₅₀, whereas there was no significant change in the slope of the regression line calculated by log-logit transformation.
These findings suggest that the coronary vasodilatory effect of adenosine is partially induced through an increase of NO release, and this action may play a role in the regulation of coronary vascular tone.