cGMP参与冠状动脉短时期缺氧性收缩反应的机制研究

Hypoxic coronary artery spasm is a mian cause for angina pectoris. It is generally considered that the role of nitric oxide (NO) is relaxing blood vessels. However, our research indicates that the short term hypoxia induced constriction of porcine coronary artery is closely related to the production and release of nitric oxide(NO) from its endothelium. Using antagnists of PDE catalysing the hydrolysis of cGMP would obviously enhance the short term hypoxia induced constriction of porcine coronary artery. Based on our results, it is postulated that cGMP may be involved in the short term hypoxia induced constriction of porcine coronary artery. In order to prove it, we will analyse the role of cGMP in the short term hypoxia induced constriction of porcine coronary artery, by using agonists and antagnists of the molecules of NO-cGMP signalling pathway and observing the changes of vessel tension and the phosphorylation level of myosin light chain. We wil further analyse the possible mechanisms of cGMP involved in the short term hypoxia induced constriction of porcine coronary artery, by detecting the changes of cGMP content and nitrated cGMP in blood vessels, and by observing the effect of nitrated cGMP on the tension of blood vessels. Our study will provide experimental and theortical bases for preventing and treating hypoxia induced coronary artery spasm.

缺氧性冠状动脉痉挛是引发心绞痛的一个主要原因。普遍认为，一氧化氮（NO）发挥着舒张血管的功能。然而，我们前期研究发现，猪冠状动脉短时期缺氧性收缩反应与内皮产生和释放的NO密切相关。使用PDE（催化降解cGMP）的阻断剂能明显增强短时期缺氧引起的猪冠状动脉收缩反应。根据前期研究结果，我们推测:cGMP可能在猪冠状动脉短时期缺氧性收缩中发挥着一定的作用。为此，我们将使用NO-cGMP信号通路中各种分子的激动剂及阻断剂，通过观察血管张力和肌球蛋白轻链磷酸化水平的变化，来探讨cGMP在猪冠状动脉短时期缺氧性收缩反应中的作用。并通过检测血管组织内cGMP的含量和硝基化cGMP的变化情况，观察硝基化cGMP对血管张力的影响，来进一步分析cGMP参与猪冠状动脉短时期缺氧性收缩反应的主要机制。本研究将为防治缺氧性冠状动脉痉挛提供实验依据和理论支持。

缺氧性冠状动脉痉挛是引发心绞痛的一个主要原因，其与内皮产生和释放的NO及其激活的下游信号分子sGC密切相关。然而，关于钙离子在NO介导的冠状动脉缺氧性收缩反应中的作用没有一个系统的研究。此外，我们前期发现：PDE阻断剂能明显增强猪冠状动脉缺氧收缩反应。然而，目前普遍认可的cGMP这一sGC催化形成的产物并没有参与血管缺氧性收缩。根据相关文献报道，我们推测：sGC可能催化生成cIMP介导猪冠状动脉缺氧性收缩。为此，我们使用了NO-sGC信号通路中各种分子的激动剂及阻断剂，通过观察血管张力以及MYPT1和肌球蛋白轻链磷酸化水平的变化，并结合高效液相色谱-质谱串联的方法检测cIMP水平，来探讨：1.钙离子浓度或者钙离子敏感度在缺氧性收缩中的作用；2.sGC是否通过催化合成cIMP介导血管缺氧性收缩；3.cIMP在细胞内是否存在PDE抑制剂对其水平的上调并参与了缺氧性收缩反应的增强。研究结果发现：1.猪冠状动脉缺氧性收缩反应的形成与其对钙离子敏感度的增强相关；2.PDE1和PDE5的阻断剂可以通过上调cIMP水平，提高猪冠状动脉对钙离子的敏感度来增强动脉缺氧性收缩。本研究对猪冠状动脉缺氧性收缩反应机制的探讨可进一步加深对缺氧性冠状动脉痉挛机制的理解，并为临床上治疗相关疾病提供潜在的治疗靶点。