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业已证明,毛冬青甲素(IA)对抑制血小板凝聚,松驰血管平滑肌和增强心肌收缩力都有显著的效应。进一步的研究证明IA在平滑肌具有钙拮抗作用,在心肌则具有钙激动作用。此文证明毛冬青甲素明显提高心肌的cAMP和cGMP水平。在血管平滑肌,IA只提高cAMP水平而不影响cGMP的含量。结果提示,心肌内cAMP的增加可能是IA促进心肌钙内外交换速率增加进而表现正性肌力作用的机理之一。而心肌内cGMP的增加则提示IA对心肌的作用可能是多方面的。另外,IA所具有的血管松驰效应可能也与其增加平滑肌cAMP水平有关。至于IA只提高心肌的cGMP水平而不影响平滑肌cGMP水平的机理尚待研究。
It has been demonstrated that IA has a significant effect on inhibiting platelet aggregation, relaxing vascular smooth muscle and enhancing myocardial contractility. Further studies have demonstrated that IA has calcium antagonism in smooth muscle and calcium stimulant in heart muscle. This article demonstrates that Mao Dong Qing Jia Su significantly increased myocardial cAMP and cGMP levels. In vascular smooth muscle, IA only increased cAMP levels without affecting cGMP levels. The results suggest that the increase of cAMP in the myocardium may be one of the mechanisms by which IA promotes the increase of the intracellular calcium exchange rate of the myocardium and further express the positive inotropic effect. The increase in myocardial cGMP suggests that the effects of IA on the myocardium may be manifold. In addition, the vasorelaxant effects of IA may also be related to its increase in smooth muscle cAMP levels. As for the mechanism by which IA only increases cGMP levels in myocardium without affecting cGMP levels in smooth muscle, the mechanism remains to be studied.